Henry Romero / Reuters

Family members and friends carry the coffin of Pemex employee Enrique Hernandez, who died in the Jan. 31 explosion at the at the headquarters of state-owned oil giant Pemex, at a cemetery in Mexico City, Feb. 4.

MEXICO CITY - The Mexican government said on Monday that a gas leak caused a blast that killed at least 37 people at the offices of state oil monopoly Pemex in Mexico City, raising fresh questions about the firm's safety record. 

Attorney General Jesus Murillo said no trace of explosives was found at the site of the explosion, the latest in a string of disasters to hit the lumbering oil giant.

New President Enrique Pena Nieto is seeking to overhaul Pemex as part of a raft of economic reforms aimed at boosting growth in Latin America's No. 2 economy.

"We have been able to determine that the explosion was caused by an accumulation of gas in the basement of the building,'' Murillo told a news conference in Mexico City. He said the gas was believed to be methane.

Murillo said the gas may have leaked from containers in a storage facility connected to where the explosion took place by a tunnel. Or it could have leaked from an aging pipeline that passed through the building.

Another possibility is that it emanated from sewage in the ground under the building, he said.

Mexico City is built on a dried-out lake bed, and the stench of sewage often hangs over parts of the downtown.

Murillo said contractors working on supports under the building needed electricity and used an extension cord, which could have caused a spark that ignited the gas.

Thursday afternoon's blast at a building at the Pemex headquarters complex in downtown Mexico City prompted speculation the incident could have been an act of sabotage.

That raised fears that drug war violence that has killed an estimated 70,000 people in the past six years could have entered a new, more sinister phase, and rattled investors.

Reform outlook
The explosion next to Pemex's flagship tower block prompted renewed criticism of the oil giant's safety record.

For years a source of national pride, Pemex has proven stubbornly resistant to change. The firm has become a touchstone for Mexico's capacity for economic reform since oil output began to fall behind the performance of other major producers.

A symbol of Mexican self-sufficiency since President Lazaro Cardenas expropriated U.S. and British oil companies in 1938 and nationalized the oil industry, Pemex has also become a byword for inefficiency and graft.

More bodies found after Mexico skyscraper blast

Pena Nieto, who took office in December, has made passing an energy reform to boost crude production a priority this year.

Geoffrey Pazzanese, who co-manages Federated Investors' $523 million Federated InterContinental Fund, said an accident would help the government push its energy reform.

"It's probably going to be positive for the reform. It underlines the need for Pemex to invest in its own capital spending,'' he said before Murillo spoke. "You have a big explosion in a building that's right in the middle of the city.

''Conspiracy theories aside, people are probably outraged about the situation and that tends to spur action," he added.

There were mixed responses on the streets of the Mexican capital to the government's news conference about the blast.

Fernando Chapa, 61, a university administrator, said the evidence seemed credible and that it looked like an accident.

''It doesn't suit anyone having an attack there. These are old buildings that have leaks. It's like in the mines," he said.

But supermarket worker Jorge Lopez was not convinced.

''I don't believe it. What a coincidence that there was a gas buildup," said Lopez, 28. ''These are the results they give us after all these days? I don't know..."

Output slump
Mexico is the world's No. 7 oil producer and a top exporter to the United States. But output has slumped from a peak of 3.4 million barrels per day in 2004 to under 2.6 million bpd now.

While the company had said it improved safety prior to the blast, fires, explosions and other safety breaches that are regular occurrences.

Mexico loses hundreds of millions of dollars a year to theft of oil carried out by drug gangs, petty criminals and corrupt workers. The Mexican government relies on oil revenues to fund nearly a third of the federal budget.

The heavy tax burden has limited Pemex's ability to fund new projects and lift crude output. The government has warned that Mexico could become a net oil importer as early as 2018 if major new oil finds cannot be developed.

The company had pinned its long-term hopes of boosting production on the deep waters of the Gulf of Mexico, where the government estimates there are significant oilfields.

The last conservative administration had helped Pemex by drawing more outside investment into mature oilfields via the auction of private contracts.

Mindaugas Kulbis / AP

Vytas Ratkevicius, a resident of Vilnius, Lithuania, prepares to light his wood stove to heat his apartment Wednesday as air temperatures dropped to 4 degrees below zero F.

VILNIUS, Lithuania — To save money during the harsh Baltic winter, Romanas Ziabkinas did something unremarkable: He turned off his central heating and installed a cheaper electric heater. Now he finds himself neck-deep in legal woes.

His utility company refused to recognize the switch and is suing him for some $10,000 in unpaid utility bills for his apartment in Lithuania's capital. "Splitting from the Soviet Union was easier than leaving this heating system," he says.

Ziabkinas plight is extreme, but his frustrations over heating costs are shared by a majority of Lithuanians, who have seen prices soar over the past several years, especially since the shuttering of its only nuclear power plant in 2009, forcing the country to import more Russian gas to keep warm.

Lithuania's decision to scrap atomic power over safety concerns has put it under a new kind of threat: intimidation from Russia, which critics say shows no hesitation to use its energy dominance to bully former vassal states.

Mindaugas Kulbis / AP

A pedestrian walks along the banks of the Neris river in chilly Vilnius, Lithuania, where residents are finding themselves increasingly squeezed by high gas prices charged by the Russian monopoly Gazprom. In the past seven years, the retail price of natural gas pumped from Siberia has increased 450 percent.

While gas prices have tended to fall globally in recent years thanks to deposits of shale gas in the U.S. and other places, Lithuanian households have looked on in horror in the past seven years as the retail cost of natural gas pumped from Siberia leapt 450 percent — from $169 to $769 per 1,000 cubic meters.

Lithuania, a country of 3 million people, currently pays Russia a wholesale price of about $540 per 1,000 cubic meters of natural gas piped from Siberia, roughly 15 percent more than Baltic neighbors Latvia and Estonia and 25 percent more than Germany.

Many Lithuanians feel they are being punished by Russia for unsolved political issues, just as the Kremlin has used gas supplies to goad Ukraine and Belarus over political and economic disputes.

Lithuania has demanded compensation from Moscow for alleged damages incurred during the Soviet occupation from 1945 to 1991 and last year enacted a European Union directive to separate gas supply and distribution, a direct blow to Russia's commercial interests in the country. Estonia and Latvia, which also receive all their gas from Russia, have done neither — and, not surprisingly, enjoy cheaper prices.

Russia's state-owned gas monopoly, Gazprom, rarely comments on gas price deals with individual countries, using the secrecy to haggle with each individual nation separately — playing one off the other — in what is seen as an extension of Kremlin foreign policy.

Mikhail Mokrushin / AFP - Getty Images, file

Gazprom chief executive Alexei Miller, left, has the ear of Russian Prime Minister Dmitry Medvedev. The two are shown at a January visit to a new power plant in Sochi.

Lithuania has a long-term supply agreement with Gazprom that expires in 2015. Russia has justified the price rises by saying the deal allows it to index gas rates to oil prices. The catch is that Russia has given discounts to friendly nations while sticking to the full price for those with which it has disputes.

"We believe Lithuania should pay a fifth less than it does now," Prime Minister Algirdas Butkevicius recently told reporters.

Lithuania's previous center-right government sued Gazprom in international arbitration court for $1.9 billion over gas price hikes and has called on the EU to investigate the company's alleged unfair pricing policies. Butkevicius, however, is willing to scrap the litigation in exchange for cheaper gas.

Regardless of the legal outcome, heating now seems a luxury many Lithuanians can't afford — and with tragic consequences. Last winter a 77-year-old pensioner in the southern district of Alytus was found frozen to death in his house. In another case, an 80-year-old woman who lived alone died in her bed in 2011, her body stuck to the frozen bed sheets.

Many people who can't afford their heating bill don't pay it, resulting in an increasingly large income hole that utilities fear they'll never recover. In Vilnius, the total amount of unpaid heating bills surpassed $15 million last year, while in Kaunas, Lithuania's second largest city, the number was $17 million.

Toma Gajauskiene, a 25-year-old Lithuanian language teacher, feels that she's drowning in unpaid heating bills for her apartment in a high-rise building. She earns some 1,200 litas ($460) per month and has a small child and unemployed husband to support.

"Last December was not too cold, but the heating bill stands at 500 litas, almost half of what I make," Gajauskiene said. "For January the bill will be at least double, but I simply cannot pay more than 300 litas for heating because my family will not have money to buy food."

One American was killed and two escaped unharmed from a natural gas complex in Algeria that was stormed by armed militants, U.S. officials said Friday. The fate of two others was unclear.

The officials said there was a total of five Americans at the In Amenas plant in eastern Algeria when the attackers seized dozens of hostages on Wednesday. The officials say two of the Americans managed to conceal themselves when the attack began and later escaped unharmed.

One U.S. citizen was found dead Friday by Algerian forces that had launched a raid on Thursday in an attempt to free the hostages, the officials said.

The deceased American was identified as Frederick Buttaccio, a U.S. official confirmed. Buttaccio's remains have been recovered from the plant and his family has been notified, the official said.

The official did not know the circumstances of Buttaccio's death.

Al-Qaida-linked militants claimed Friday that they were holding two American hostages and would exchange them for two people being held in the United States — the blind sheik Omar Abdel Rahman, convicted in the 1993 bombing of the World Trade Center and Aafie Siddiqque a 40-year-old Pakistani neuroscientist and mother of three, who was convicted of attacking U.S. soldiers in Afghanistan.

That would appear to account for all five Americans thought to have been at the plant, one U.S. official said, if the militants are telling the truth.  

On Friday, the Algerian military had launched a second raid on the multinational cabal of kidnappers — led by a one-eyed al-Qaida associate — who laid siege to the In Amenas gas plant on Wednesday, state TV reported.

The situation was fluid, but the U.S. said one thing was carved in stone: It would not be cutting any deals with the captors.

"The United States does not negotiate with terrorists," State Department spokeswoman Victoria Nuland said of reports the militants were seeking the release of Sheik Omar Abdel Rahman, who is serving a life term for the 1993 bombing of the World Trade Center, and Aafia Siddiqui, a Pakistani scientist convicted of trying to kill U.S. soldiers after being arrested in Afghanistan in 2008.

Nuland confirmed there were Americans still being held alive but did not say how many.

The official Algerian news service APS said a total of 132 foreign nationals were taken hostage, and 100 had been freed by midday Friday. It said more than 500 Algerians had also been rescued.

Citing a security source, APS said 12 hostages, including some Westerners, were killed when Algeria staged its first rescue raid on Thursday without consulting other countries in advance. Eighteen militants were killed, it reported.

McFaul family via Reuters

Belfast native Stephen McFaul (right) is pictured with his sons Dylan (left) and Jake in this family handout photo taken four years ago and made available Thursday.

NBC News could not confirm the figures. The French government confirmed one of its citizens had died, and its defense minister said in an interview on France 3 TV Saturday morning that he believed no more French nationals were being held at the plant.

One worker told Reuters that the hostage-takers were out for blood.

"The terrorists told us at the very start that they would not hurt Muslims but were only interested in the Christians and infidels," said the man, who gave his name as Abdelkader. "'We will kill them,' they said."

The brother of escapee Stephen McFaul said the hostages had their mouths taped and their necks draped with explosives. They were being trucked around the compound when the Algerian military hit the compound with explosives, he told Reuters.

"The truck my brother was in crashed and at that stage Stephen was able to make a break for his freedom," Brian McFaul said after speaking with his brother’s wife. "He presumed everyone else in the other trucks was killed."

A French catering employee who worked at the plant said he spent 40 hours hiding under a bed after the militants stormed in Wednesday with a spray of gunfire, only emerging when the soldiers arrived.

"I could see myself ending up in a wooden box," Alexandre Berceaux told Europe 1 radio.

One rescued hostage told Algerian TV that the ordeal was an "exciting episode" and he was "impressed" with the army.

"I feel sorry for anybody who has been hurt, but other than that, I quite enjoyed it," the man said.

Algerian TV via Reuters TV

A British escapee, interviewed by Algerian TV, says the Algerian army did a "fantastic job" with Thursday's rescue.

Another said he was "very, very relieved to be out."

"Obviously, we still don't really know what is happening back on the site, so as much as we are glad to be out, our thoughts are with colleagues who are still there at the moment," he said on Algerian TV.

The militants' attack on the plant, operated in part by BP, was reportedly masterminded by Mokhtar bel Mokhtar, an Algerian with ties to al-Qaida who specializes in lucrative kidnappings and smuggling, according to U.S. officials. He earned the nickname Mr. Marlboro for trafficking cigarettes.

The raiding jihadists were described as a motley crew by an escaped radio operator who told Reuters: "Some were clean, others were dirty, some with beards, others without, and among them a French national with sunglasses."

The Mauritanian news agency ANI reported the group was retaliating over French military action against Islamic incursions in neighboring Mali. But the French operation began just a week ago and the assault on the plant appeared to be long-planned.

On Friday, another possible motive emerged, as ANI said the militants put forth the offer of the prisoner swap.

The offer was not verified by NBC News, but an ANI editor told The Associated Press the kidnappers’ spokesman began calling Thursday with "sounds of war in the background" and "threatened to kill all the hostages if the Algerian forces tried to liberate them."

British Prime Minister David Cameron told the House of Commons in London that Algeria maintains it green-lighted Thursday’s rescue raid because hostages’ lives were in danger when it appeared the militants were trying to spirit them out of the compound.

Secretary of State Hillary Rodham Clinton said she spoke with the prime minister of Algeria on Friday and requested that the "utmost care" be taken to protect the hostages.

"This is an extremely dangerous situation," she said. "No one knows better than Algeria how ruthless these groups are."

Kari Huus, Catherine Chomiak and Courtney Kube of NBC News and The Associated Press and Reuters contributed to this report.

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Algerian militant dubbed 'Mr Marlboro' raked in millions from kidnappings

The fate of dozens of hostages seized by Islamists at a gas field in Algeria remained unclear early Friday, hours after the Algerian military stormed the site.

At least six people, and perhaps many more, were killed, The Associated Press reported, and dozens were unaccounted for.

Algerian state media reported Thursday evening that the military operation had ended at the remote desert facility where dozens of workers — including three Americans — had been held hostage. The Algerian government was reported as saying two Filipinos and two British hostages had been killed.

Accounts of the number of hostages and militants killed in the operation differed wildly — ranging from four to 35 — in reports from regional sources cited by The Associated Press and Reuters.

Among those unaccounted for were Americans, Britons, French, Norwegians, Romanians, Malaysians, Japanese and Algerians.

Some of the hostages reportedly escaped from the natural gas pumping plant, near In Amenas, close to the border with Libya and 800 miles from the Algerian capital.

An unknown number of hostages left the country on a charter flight and were expected to land at London's Gatwick airport near midnight Thursday, according to BP, which operates the gas complex. The plane had not arrived as of 3:15 a.m. Friday.

The Islamist militants stormed the plant and workers' housing before dawn on Wednesday seizing up to 41 hostages in one of the biggest international hostage incidents in decades.

The militants have demanded an end to the French military campaign in Mali where ground troops and air forces of the former colonial power are backing Mali's military in offensive against Islamist rebels linked to al-Qaida in that country.

The group that has claimed responsibility for the gas plant raid is said to be led by an Islamic militant called Mokhtar bel Mokhtar, whose nicknames include "The Uncatchable" and "Mr. Marlboro."

According to the AP, militants with the Masked Brigade, a Mali-based al-Qaida offshoot, provided updates through a Mauritanian news organization that said the Algerians attacked when the militants tried to move hostages from the energy complex. The group claimed that 35 hostages and 15 militants died but seven hostages survived the helicopter attack on its convoy.

An Algerian security official says the decision to send forces came because the militants were being stubborn and wanted to flee with the hostages.

U.S. officials called the hostage situation "murky" and said the United States is working with the Algerian government and other affected nations to try to resolve the situation as quickly and securely as possible.

"It's in a remote area of Algeria, near the Libyan border," Secretary of State Hillary Clinton said. "The security of our Americans who are held hostage is our highest priority, but of course we care deeply about the other Algerian and foreign hostages as well."

Clinton said she could not provide any additional information about the situation. 

An Ireland government spokesman said Thursday that an Irish national held at the In Amenas gas plant had "made contact with his family and is understood to be safe and well, and no longer a hostage."

Sky News in London identified the Irish survivor as Stephen McFaul, 46, from west Belfast.

In an interview with the television station, McFaul's father Christopher said he was "delighted" by the news but added he felt "sorry for the other hostages that are still there."

He also described the last 48 hours as "hell".

Stephen McFaul's son, Dylan, also spoke to the Sky reporters: "I can't even explain the excitement. I can't wait until he gets home again," he said, adding that he would tell his father "he's never going back there and I'm not letting him".

A local resident near the plant told Reuters the Algerian military had opened fire and that "many people" were killed.

Faycal Metaqui, a journalist at Algerian newspaper El Watan, told French news channel BFM that he was unable to confirm with authorities the earlier reports that some hostages had escaped.

"Sadly, there have been some reports of casualties, but we are still lacking any confirmed or reliable information," said a statement from oil giant BP, which is a joint owner of the plant.

Related content:

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Nancy Ing, Jim Miklaszewski and Courtney Kube of NBC News, contributed to this report.

Three Americans were among dozens of foreign nationals kidnapped by heavily armed militants who attacked a gas field in Algeria on Wednesday, U.S. officials said.

A militant group claimed the raid was launched in retaliation for France's military intervention in neighboring Mali, Reuters reported, citing local media.

The hostage situation, described as a "terrorist attack" by State Department spokeswoman Victoria Nuland, was unfolding at a gas operation at In Amenas — a joint venture including oil giant BP, the Norwegian oil firm Statoil and the Algerian state company Sonatrach.

BP said in a statement that the site was "attacked and occupied by a group of unidentified armed people."

Reuters said that according to regional media reports, the raiders killed three people, including a Briton and a French national, but there was no way to confirm the account. Reuters did not report the citizenship of the third person.

Al-Qaida in the Islamic Maghreb, which operates across borders in the Sahara desert, claimed it had captured the workers in retaliation for France's intervention in Mali, Reuters reported, citing regional news agencies.

France has been using Algeria's air space for attacks against al-Qaida linked militants in Mali since last week.

Western government officials had not yet linked Wednesday's attack to the conflict in Algeria's southern neighbor. Algeria and neighboring Mali are former colonies of France.

"The Algerian authorities will not respond to the demands of the terrorists and will not negotiate,'' Interior Minister Daho Ould Kablia was quoted as saying by Algeria's official APS news agency.

One of the kidnappers, reportedly contacted by Mauritania's news agency ANI, warned that any attempt to free the hostages would come to a "tragic end." The militants had placed mines around the site of the kidnapping, according to that unconfirmed report.

The U.S. government is in contact with Algerian authorities, the British Embassy in Algiers, BP's security office in London and the Diplomatic Security office in Washington, State Department spokeswoman Victoria Nuland said in a briefing on Wednesday.

French President Francois Hollande said he was also in contact with Algiers and other governments about the attack.

A picture of who was being held hostage — with various reports that the total number was 41 — remains incomplete, but citizens of at least six countries are in the group.

There are three Americans in the group, a senior U.S. official told NBC. An earlier report had put the number at seven.

The State Department’s Nuland confirmed that Americans were among the hostages, but she would not release names, numbers and other details "in order to protect their safety."

Norwegian Prime Minister Jens Stoltenberg told a news conference that 13 Norwegian citizens were among the hostages. Three Algerian Statoil employees and one Canadian were in the hostage group, the company said. Statoil is a minority shareholder in the venture.

One Irish national was abducted, an Irish government official said, and British Prime Minister David Cameron said "several" British citizens were among the hostages.

A spokesman for the Japanese government said it had set up a task force to investigate reports of Japanese hostages.

A reporter for Japan's NHK television managed to call a Japanese worker in Algeria, Reuters reported. The worker said he got a phone call from a colleague at the gas field.

"It was around 6 a.m. this morning. He said that he had been hearing gunshots for about 20 minutes," the worker said. "I wasn't able to get through to him since."

The U.S. government issued an emergency message to Americans in the country through the embassy in Algiers, warning them to avoid large gatherings, protests or demonstrations.

"U.S. citizens should review their personal security plans, remain aware of their surroundings, including local events, and monitor local news stations for updates," it read, in part. "Maintain a high level of vigilance and take appropriate steps to enhance your personal security and follow instructions of local authorities.

The Amenas gas field is about 800 miles southeast of Algiers and about 35 miles west of the Libyan border.

Oil major BP said it believed the operation had been shut down after the attack, which took place at about 5 a.m. local time. The company said the field had been producing about 160,000 barrels of oil equivalent per day — more than 10 percent of the country's overall gas output, Reuters reported.

Related content:
France launches tough ground offensive against Mali's Islamist rebels 

Jim Miklaszewski, Courtney Kube, Ian Johnston, Arata Yamamoto and Alastair Jamieson of NBC News, and Reuters, contributed to this report.

Muhammad Hamed / Reuters

Jordanian gendarmerie police stand guard to separate pro-government supporters from anti-government protesters Tuesday.

Demonstrations and calls for general strikes hit key U.S. ally Jordan after the country’s prime minister added to the country’s economic problems by announcing price hikes for gas and other fuel.

Abdullah Ensour's announcement on state television Tuesday cited a need to offset $5 billion in state losses by increasing fuel costs.

It sparked protests in the capital, Amman, and at least 12 other cities across Jordan.

The protesters, spanning an array of different political groups, also targeted King Abdullah II -- a rare public display against the monarch.

Criticizing the king in public is forbidden in Jordan and is punishable by up to three years in jail.

"Revolution, revolution, it is a popular revolution," chanted about 2,000 in an impromptu demonstration at a main Amman square, housing the Interior Ministry and other vital government departments.

"Freedom is from God, in spite of you, Abdullah," they shouted.

Muhammad Hamed / Reuters

Protesters rally Tuesday following an announcement that Jordan would raise fuel prices.

Tough test for regime
Cars jammed gas stations to stock up on fuel before the price hike takes effect on Wednesday.

The protests looked set to escalate toward the end of the week, setting a tough test for Jordan’s regime, although military suppression tactics - commonly used in Egypt and elsewhere – are highly unusual.

The country has traditionally been one of the most stable in the Middle East, despite its position at the fulcrum of the region’s deepest conflicts in recent years. Its longest border, with Israel, has been peaceful since a 1993 treaty.

Radical cleric linked to al-Qaida set free after UK court ruling

Although a relatively wealthy country, Jordan lacks natural resources and has been stretched economically by decades of refugees from neighboring conflicts, who have pushed up demand for real estate and commodities.

Ensour, the prime minister, said a type of fuel used in public transport will rise in price by 14 percent, while kerosene oil used for household heating will go up by 28 percent.

Cooking gas will jump 54 percent, he said. Many low-income Jordanians use the gas for heating.

Pipeline repeatedly blown up
Disruptions in cheap Egyptian gas shipments cost Jordan an extra $7 million a day, the government said, pushing the budget deficit to a record high of nearly $3 billion this year.

The pipeline that carries Egyptian natural gas to Israel and Jordan has been blown up more than a dozen times over the past year by militants in Egypt's Sinai desert, halting shipments. Jordan has switched to the more expensive fuel oil to generate electricity.

Jordan foils plot to bomb Western targets, arrests 11

In some cities in Jordan's south, inhabited by tribal Bedouins who are traditional supporters of the king, hundreds of protesters took to the streets to chant slogans calling for the ouster of the prime minister, but also criticizing the king.

In Mazar, dozens of protesters burned down the main court building after stealing documents, said Yazan Naanah, a resident who said he saw the arson but did not take part in the protest.

Further south in Maan, a hotbed for Jordanian Muslim militants, 500 protesters blocked the streets, burning tires and throwing stones at riot police, who were firing tear gas, a city official said, insisting on anonymity because he is not allowed to make press statements. He said there were no immediate reports of injuries.

NBC's Ayman Mohyeldin and Reuters contributed to this report.

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Updated at 10:10 p.m. ET: A huge explosion rocked Venezuela's biggest oil refinery and unleashed a ferocious fire on Saturday, killing at least 39 people and injuring more than 80 others in one of the deadliest disasters ever to hit the country's key oil industry.

Balls of fire rose over the Amuay refinery, among the largest in the world, in video posted on the Internet by people who were nearby at the time. Government officials pledged to restart the refinery within two days and said the country has plenty of fuel supplies on hand to meet domestic needs as well as its export commitments.

The explosion shattered walls of nearby shops, ripped out windows from homes and left the surrounding streets covered with rubble and twisted scraps of metal.

President Hugo Chavez declared three days of mourning and ordered an investigation to determine the cause of the explosion. "This affects all of us," Chavez said by phone on state television. "It's very sad, very painful."

Vice President Elias Jaua, who traveled to the area in western Venezuela, said on state television late Saturday that at least 39 people were killed by the explosion, up from the earlier death toll of 26. He said that the dead included 18 National Guard troops and that six of the bodies had not yet been identified. Other officials said earlier that the dead included a 10-year-old boy.

In a neighborhood next to the refinery, shopkeeper Yolimar Romero said she was at her computer when a shock wave swept over the area shortly after 1 a.m.

"At that instant, the whole house shook as if it were an earthquake," she said. "The windows went flying off with their frames and everything."

Electricity was knocked out, leaving Romero in the dark and her house filled with smoke. She found a flashlight and started looking for her husband and three children.

Outside on the street, the family saw scattered hunks of brick walls and ruins of a National Guard post and about 20 other homes. Bodies were being pulled from buildings down the street.

At least 86 people were injured, nine of them seriously, Health Minister Eugenia Sader said at a hospital where the wounded were taken. She said 77 people suffered light injuries and were released.

Officials said firefighters had largely controlled the fire at the refinery on the Paraguana Peninsula, where flames were still visible on Saturday night after billowing dark smoke all day.

The blast occurred about 1:15 a.m. when a natural gas leak created a cloud that ignited, Oil Minister Rafael Ramirez said.

"That gas generated a cloud that later exploded and has caused fires in at least two tanks of the refinery and surrounding areas," Ramirez said.

Images shortly after the explosion showed the flames casting an orange glow against the night sky, and injured survivors on a stretcher and in a wheelchair. The bloodied bodies of victims were loaded onto pickup trucks.

Ramirez said a panel of investigators was being formed to determine the cause of the gas leak. A prosecutor was appointed to lead the investigation and troops were deployed to the area.

While the cause of the disaster remains unclear, some oil workers and critics of Chavez's government have recently pointed to increasing numbers of smaller accidents and spills as an indication of problems within the state-run company.

"We warned that something was going to happen, a catastrophic event," said Ivan Freites, secretary general of a 1,200-member union of oil and natural gas industry workers in Falcon state where the refinery is located. He spoke in a telephone interview from an area near the refinery, where he could see the flames raging in the distance.

Daniela Primera / AP

An explosion at a Venezuelan oil refinery triggered the fire seen at right early Saturday.

The refinery complex's general manager, Jesus Luongo, denied that a lack of maintenance was to blame, saying in the past three years more than $6 billion has been invested in maintaining the country's refineries.

Ramirez said the explosion hit an area of storage tanks, damaging nine tanks.

"All of the events happened very quickly," Ramirez said. "When we got here in the middle of the night, at 3 or 3:30 in the morning, the fire was at its peak."

The oil minister said that supplies of fuel had been cut off to part of the refinery and that firefighters were using foam to extinguish the flames in one of the remaining tanks.

"This regrettable and sad event is controlled, is under control," Ramirez said on television, while plumes of smoke continued to billow.

Amuay is part of the Paraguana Refinery Complex, which also includes the adjacent Cardon refinery. Together, the two refineries process about 900,000 barrels of crude per day and 200,000 barrels of gasoline. Venezuela is a major supplier of oil to the U.S. and a member of the Organization of Petroleum Exporting Countries.

Ramirez said the state oil company Petroleos de Venezuela SA should be able to "restart operations in a maximum of two days."

"We want to tell the country that we have sufficient inventories of fuel. We have 10 days of inventory of fuel," Ramirez said. He said the country's other refineries were operating at full capacity and would be able to "deal with any situation in our domestic market."

An official of the state oil company, known as PDVSA, said the country also has enough supplies on hand to guarantee its international supply commitments. The official spoke on condition of anonymity because he wasn't authorized to speak publicly about the matter.

In terms of international oil markets, the disaster is not likely to cause much of a ripple, said Jason Schenker, an energy analyst and president of Austin, Texas-based Prestige Economics LLC. Noting that other refinery accidents and shutdowns regularly occur around the world, he said: "There's likely to be relatively limited impact on global crude or product pricing."

"The real tragedy," he said, "is that these events continue to happen, not just in Venezuela but everywhere. It is a dangerous business."

Gustavo Coronel, an energy consultant and former PDVSA executive, called the tragedy "probably the worst one the oil industry has had in many years."

"Accidents happen, of course, although the problem with PDVSA is the inordinate amount of accidents that have taken place during the last years," Coronel said. Considering the overall record, "we are not talking about bad luck but about lack of maintenance and inept management," he said.

The labor leader Freites, who has worked at the refinery for 29 years, said workers had repeatedly alerted state oil company officials to problems that they feared could lead to an accident. "We've been complaining about problems and risks, including fires, broken pipes and a lack of spare parts," Freites said.

One opposition group comprised of former PDVSA employees, Gente del Petroleo, or Oil People, said it could not yet pass judgment on the cause of the explosion. But it but noted there had been ample concerns about lack of maintenance and poor management.

The group said in a statement that since 2003, 79 other serious accidents have been reported at the Paraguana Refinery Complex, collectively killing a total of 19 workers and injuring 67 others.

Opposition leader Henrique Capriles, who is challenging Chavez in the country's Oct. 7 presidential election, expressed condolences to the victims and their families.

"We Venezuelans are one, and we grow in the face of this type of situations," Capriles said.

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An explosion in England left at least one child dead after five terraced houses were destroyed in a suspected gas blast.

Firefighters continue searching through the rubble in Manchester for anyone who might be trapped. One man was taken to the hospital with severe burns, BBC reported.

"It's like a war zone - tiles that have blown off literally across the streets, there's just debris everywhere. It's mad," Alex Perkins, who lives nearby, told BBC. "It's just empty, there's nothing there, just bricks on the floor, just rubble."

Georgian Ulla, who also lives on the street, told the BBC her house "shook like it was an earthquake."

"All the lights shook - I thought someone was breaking in to begin with," she added. "First thing that I saw was all the toys on the floor. Apparently there are kids that live in the house."

The explosion was felt half a mile away, and shock waves broke windows, set off car alarms and littered the area with fragments of roof slates. At least 100 homes were evacuated, and 30 firefighters were on the scene.

Craig Needham, who runs a nearby garage, told the BBC that he and his employees ran outside when they heard the blast.

"We could just see a black plume. We thought a bomb had dropped," he said.

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Asahi Shimbun / AFP/Getty Images

FILE PHOTO: On March 20, 1995, subway passengers waited to receive medical attention after inhaling nerve gas.

Updated at 7:11 a.m. ET: TOKYO - After 17 years on the run, the last remaining member of the Japanese doomsday cult wanted for the deadly 1995 sarin gas attack on the Tokyo subway system was arrested by police Friday.

Katsuya Takahashi, a former member of the Aum Shirikyo cult who is believed to have been responsible for transporting cult members to the site of the subway attack, which left 13 dead and 54 wounded.

He was arrested at a 24 hour comic book cafe after a tip-off to Tokyo police from a cafe employee.

The search for Takahashi had been dormant for close to two decades, but took a dramatic turn earlier this month when another former cult member Naoko Kikuchi who had been wanted for her involvement in the sarin production, was apprehended by the police.

Suspect in 1995 Tokyo gas attack arrested in Japan

After questioning Kikuchi, investigators were able to piece together the last 17 years of Takahashi's life, leading them to the construction company where Takahashi had been working up until Kikuchi's arrest.

From there, surveillance videos surfaced capturing images of Takahashi at a nearby bank and a shopping center.

Takahashi has told police that he was only following orders from the cult, and wasn't aware of some of the operations' objectives.

AP / Tokyo Metropolitan Police Department via Kyodo News

Video footage of a surveillance camera released by Tokyo Metropolitan Police Department shows Katsuya Takahashi, a former member of Aum Shinrikyo cult, at a bank near Tokyo.

Although the principle ringleaders of the cult have long been convicted and sentenced, authorities are hoping that this arrest of the last Aum Shirikyo suspect will shed new facts and details on the cults' most heinous crimes.

The cult was founded in 1984 by leader Shoko Asahara on a doomsday principle that World War III would be instigated by the United States. Asahara predicted the world would come to an end in 1997.  

Msnbc.com staff contributed to this report.

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Lucas Jackson / Reuters, file

U.S. Navy safety swimmers stand on the deck of the Virginia class submarine USS New Hampshire after it surfaced through thin ice during exercises underneath ice in the Arctic Ocean north of Prudhoe Bay, Alaska March 19, 2011.

YOKOSUKA, Japan -- To the world's military leaders, the debate over climate change is long over. They are preparing for a new kind of Cold War in the Arctic, anticipating that rising temperatures there will open up a treasure trove of resources, long-dreamed-of sea lanes and a slew of potential conflicts. 

By Arctic standards, the region is already buzzing with military activity, and experts believe that will increase significantly in the years ahead. 

Last month, Norway wrapped up one of the largest Arctic maneuvers ever — Exercise Cold Response — with 16,300 troops from 14 countries training on the ice for everything from high intensity warfare to terror threats. Attesting to the harsh conditions, five Norwegian troops were killed when their C-130 Hercules aircraft crashed near the summit of Kebnekaise, Sweden's highest mountain.

The U.S., Canada and Denmark held major exercises two months ago, and in an unprecedented move, the military chiefs of the seven main Arctic powers — Canada, the U.S., Russia, Iceland, Denmark, Sweden and Finland — are to gather at a Canadian military base in May to specifically discuss regional security issues. 

None of this means a shooting war is likely at the North Pole any time soon. But as the number of workers and ships increases in the High North to exploit oil and gas reserves, so will the need for policing, border patrols and — if push comes to shove — military muscle to enforce rival claims. 

High stakes
The U.S. Geological Survey estimates that 13 percent of the world's undiscovered oil and 30 percent of its untapped natural gas is in the Arctic.

Shipping lanes could be regularly open across the Arctic by 2030 as rising temperatures continue to melt the sea ice, according to a National Research Council analysis commissioned by the U.S. Navy last year. 

UK report analyzes risks of Arctic development

What countries should do about climate change remains a heated political debate. But that has not stopped north-looking militaries from moving ahead with strategies that assume current trends will continue. 

Russia, Canada and the United States have the biggest stakes in the Arctic. With its military budget stretched thin by Iraq, Afghanistan and more pressing issues elsewhere, the United States has been something of a reluctant northern power, though its nuclear-powered submarine fleet, which can navigate for months underwater and below the ice cap, remains second to none. 

Lucas Jackson / Reuters, file

U.S. Navy watch a display in the control room of the Virginia class submarine USS New Hampshire as it surfaces during exercises underneath ice in the Arctic Ocean north of Prudhoe Bay, Alaska March 20, 2011.

Russia — one-third of which lies within the Arctic Circle — has been the most aggressive in establishing itself as the emerging region's superpower. 

Rob Huebert, an associate political science professor at the University of Calgary in Canada, said Russia has recovered enough from its economic troubles of the 1990s to significantly rebuild its Arctic military capabilities, which were a key to the overall Cold War strategy of the Soviet Union, and has increased its bomber patrols and submarine activity. 

Huebert said that has in turn led other Arctic countries — Norway, Denmark and Canada — to resume regional military exercises that they had abandoned or cut back on after the Soviet collapse. Even non-Arctic nations such as France have expressed interest in deploying their militaries to the Arctic. 

Some Himalayan glaciers are actually growing

"We have an entire ocean region that had previously been closed to the world now opening up," Huebert said. "There are numerous factors now coming together that are mutually reinforcing themselves, causing a buildup of military capabilities in the region. This is only going to increase as time goes on." 

Noting that the Arctic is warming twice as fast as the rest of the globe, the U.S. Navy in 2009 announced a beefed-up Arctic Roadmap by its own task force on climate change that called for a three-stage strategy to increase readiness, build cooperative relations with Arctic nations and identify areas of potential conflict. 

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"We want to maintain our edge up there," said Cmdr. Ian Johnson, the captain of the USS Connecticut, which is one of the U.S. Navy's most Arctic-capable nuclear submarines and was deployed to the North Pole last year. "Our interest in the Arctic has never really waned. It remains very important." 

US 'inadequately prepared'
But the U.S. remains ill-equipped for large-scale Arctic missions, according to a simulation conducted by the U.S. Naval War College. A summary released last month found the Navy is "inadequately prepared to conduct sustained maritime operations in the Arctic" because it lacks ships able to operate in or near Arctic ice, support facilities and adequate communications.

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The findings indicate the Navy is entering a new realm in the Arctic," said Walter Berbrick, a War College professor who participated in the simulation. "Instead of other nations relying on the U.S. Navy for capabilities and resources, sustained operations in the Arctic region will require the Navy to rely on other nations for capabilities and resources." 

He added that although the U.S. nuclear submarine fleet is a major asset, the Navy has severe gaps elsewhere — it doesn't have any icebreakers, for example. The only one in operation belongs to the Coast Guard. The U.S. is currently mulling whether to add more icebreakers.

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Acknowledging the need to keep apace in the Arctic, the United States is pouring funds into figuring out what climate change will bring, and has been working closely with the scientific community to calibrate its response. 

"The Navy seems to be very on board regarding the reality of climate change and the especially large changes we are seeing in the Arctic," said Mark C. Serreze, director of the National Snow and Ice Data Center at the Cooperative Institute for Research in Environmental Sciences University of Colorado. "There is already considerable collaboration between the Navy and civilian scientists and I see this collaboration growing in the future." 

The most immediate challenge may not be war — both military and commercial assets are sparse enough to give all countries elbow room for a while — but whether militaries can respond to a disaster. 

Heather Conley, director of the Europe program at the London-based Center for Strategic and International Studies, said militaries probably will have to rescue their own citizens in the Arctic before any confrontations arise there. 

"Catastrophic events, like a cruise ship suddenly sinking or an environmental accident related to the region's oil and gas exploration, would have a profound impact in the Arctic," she said. "The risk is not militarization; it is the lack of capabilities while economic development and human activity dramatically increases that is the real risk."