SITE Intel Group via AP, file

Known as the "one-eyed," Moktar Belmoktar's profile soared after the mid-January attack and mass hostage-taking on a huge Algerian gas plant.

Chad's military chief announced late Saturday that his troops deployed in northern Mali had killed Moktar Belmoktar, the terrorist who orchestrated the attack on a natural gas plant in Algeria that left 36 foreigners dead.

The French military, which is leading the offensive against al-Qaida-linked rebels in Mali, said they could not immediately confirm the information.

Local officials in Kidal, the northern town that is being used as the base for the military operation, cast doubt on the assertion, saying Chadian officials are attempting to score a PR victory to make up for the significant losses they have suffered in recent days.

Known as the "one-eyed," Belmoktar's profile soared after the mid-January attack and mass hostage-taking on a huge Algerian gas plant. His purported death comes a day after Chad's president said his troops had killed Abou Zeid, the other main al-Qaida commander operating in northern Mali.

If both deaths are confirmed, it would mean that the international intervention in Mali had succeeded in decapitating two of the pillars of al-Qaida in the Sahara.

"Chad's armed forces in Mali have completely destroyed a base used by jihadists and narcotraffickers in the Adrar and Ifoghas mountains" of northern Mali, Army Chief of Staff Gen. Zakaria Ngobongue said in a televised statement on state-owned National Chadian Television. "The provisional toll is as follows: Several terrorists killed, including Moktar Belmoktar."

The French military moved into Mali on Jan. 11 to push back militants linked to Belmoktar and Abou Zeid and other extremist groups who had imposed harsh Islamic rule in the north of the vast country and who were seen as an international terrorist threat.

France is trying to rally other African troops to help in the military campaign, since Mali's military is weak and poor. Chadian troops have offered the most robust reinforcement.

In Paris, French military spokesman Col. Thierry Burkhard said that he had "no information" on the possibility that Belmoktar was dead. The Foreign Ministry refused to confirm or deny the report.

A spokesman for Chad's presidential palace did not immediately return a request for comment.

In Kidal in northern Mali, an elected official, who requested anonymity because he was not authorized to speak to the press, said that he did not believe that Belmoktar was dead and waved off the claim as an attempt by Chad to explain the loss of dozens of their troops to a grieving nation.

"These last few weeks, the Chadians have lost a significant number of soldiers in combat. (Claiming that they killed Belmoktar) is a way to give some importance to their intervention in Mali," said the official, who keeps in close contact with both French and Malian commanders in the field.

Belmoktar, an Algerian, is believed to be in his 40s, and like his sometimes partner and sometimes rival, Abou Zeid, he began on the path to terrorism after Algeria's secular government voided the 1991 election won by an Islamic party.

Both men joined the Armed Islamic Group, or GIA, and later its offshoot, the GSPC, a group that carried out suicide bombings on Algerian government targets.

Around 2003, both men crossed into Mali, where they began a lucrative kidnapping business, snatching European tourists, aid workers, government employees and even diplomats and holding them for multimillion-dollar ransoms.

The Algerian terror cell amassed a significant war chest, and joined the al-Qaida fold in 2006, renaming itself al-Qaida in the Islamic Maghreb.

Belmoktar claims he trained in Afghanistan in the 1990s, including in one of Osama Bin Laden's camps. It was there that he reportedly lost an eye, earning him the nickname "Laaouar," Arabic for "one-eyed."

Until last December, Belmoktar and Abou Zeid headed separate brigades under the flag of al-Qaida's chapter in the Sahara. But after months of reports of infighting between the two, Belmoktar peeled off, announcing the creation of his own terror unit, still loyal to the al-Qaida ideology but separate from al-Qaida in the Islamic Maghreb.

It was this group that launched the fatal attack on a BP-operated natural gas plant in southeastern Algeria in retaliation for the French-led military intervention in Mali.

In the attack and in the subsequent rescue attempt, 37 people, all but one of them foreigners, were killed inside the complex. Belmoktar claimed responsibility for the attack within hours, immediately catapulting him into the ranks of international terrorists.

In addition to the alleged killing of Belmoktar, Ngobongue said that Chad's military had also nabbed 60 of the jihadists' cars, electronic equipment and weapons. "The raid is still ongoing," he said.

Related:

Chad claims to have killed feared al-Qaida commander in Mali

In Texas on Tuesday, the FBI told Erin Lovelady that her father was one of three Americans who had been killed in the terrorist assault on an Algerian gas facility last week. The news destroyed a bit of his daughter's faith.

"My whole life he always told me that good things happen to good people and that I was a good person and good things were going to happen for me," she said Tuesday.

The grief of the Lovelady family is a poignant reminder of the growing concern among U.S. counterterrorism officials that the amorphous al-Qaida-affiliated groups contesting swathes of northern Africa are increasingly coordinating their strategy with al-Qaida central in Pakistan –  the remnants of the terrorist organization founded by Osama bin Laden.

Victor Lovelady had gone overseas because the month-on, month-off schedule gave him more time to be with his family.

"He felt 100 percent comfortable going there and he wanted that, it was never about money, it was never about that, he was going to retire and you know ...," Erin Lovelady said, her voice trailing off.

Pat Sullivan / AP

Mike Lovelady, left, sits with niece Erin Lovelady as she wipes her tears and talks about her father Victor in Nederland, Texas, on Tuesday.

Victor Lovelady was one of at least 37 foreign hostages executed by their captors or killed in the Algerian rescue mission.  The government in Algiers, aware that Western governments were angered by what they perceived as hurried decision-making on its part, released videotape on Tuesday of kidnappers carrying out executions.

"It should have been no surprise that the Algerians were going to be aggressive," said Michael Leiter, former director of the U.S. National Counter Terrorism Center and now an NBC News counterterrorism analyst. The Algerian government  couldn't afford to have prolonged hostage crisis in the midst of their southern gas fields that are crucial to its economy, he said. 

While analysts noted that the attacks did not affect the price of natural gas, they pointed out that the price of gas has already dropped and that any instability in Algeria would make negotiating with prospective partners or financiers more problematic.

“They had to consider that," Leiter said.

Now, with the Algerian standoff ended in a bloody massacre, U.S. and other Western officials are wondering where the terrorists will strike next. They note that with the death of the three Americans in Algeria, and the killing of U.S. Ambassador Chris Stevens and three others in Libya, al-Qaida in the Islamic Magreb (AQIM) has suddenly become the most active of the "affiliates" of the central terrorist organization founded by bin Laden.

They point to October's video message from bin Laden’s successor, al-Qaida central leader Ayman al-Zawahri  to al-Qaida affiliates, in which he suggested that they engage in kidnappings to free prisoners held in the West, particularly Omar Abdul Rahman. Rahman, the so-called blind sheikh imprisoned in the U.S. for his role in the 1993 conspiracy to topple the World Trade Center, was one of two convicted terrorists the Algeria hostage takers demanded in return for Americans they held and later killed.

The other was Aafia Siddiqui, convicted of planning attacks on U.S. soldiers in Afghanistan.

Mokhtar bel Mokhtar, whose Signatories in Blood group claimed responsibility for the Algerian attack, has said that his organization been in touch with al-Qaida in Pakistan and that the assault on the natural gas plant was conducted on the umbrella group’s behalf.

Although there's no indication that AQIM is planning attacks on the U.S., there is intelligence suggesting that its members have planned attacks in France. That's one reason that France decided last week to move troops and arms into Mali to stop fundamental Islamists from reaching the capital of Bamako.

On Tuesday, the U.S. took another step in helping the French. American C-17s began transporting French troops and equipment to near the front line of the fighting in Mali.    

Richard Engel is NBC News' Chief Foreign Correspondent. Robert Windrem is a Senior Investigative Producer.

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ALGIERS, Algeria — The U.S. State Department on Monday confirmed that three American citizens were among those killed during the hostage-taking by Islamic militants at a gas field in Algeria.

The death toll from the four-day siege deep in the Sahara has risen to at least 67, Algerian Prime Minister Abdelmalek Sellal said Monday on Algerian televsion. The number includes 38 foreign workers and 29 militants who died in the crisis which came to an end in a bloody confrontation with Algerian forces.

Five foreigners remained unaccounted for, Sellal said.

A Japanese government source said the Algerian government had informed Tokyo that nine Japanese had been killed, the highest toll among the non-Algerians working there.

State Department spokeswoman Victoria Nuland on Monday identified the three Americans who were killed as Victor Lynn Lovelady, Gordon Lee Rowan and Frederick Buttaccio, who had been named earlier.

"We are also aware of seven U.S. citizens who survived the attack," Nuland said. "Due to privacy considerations, we have no further information to provide.

"We will continue to work closely with the Government of Algeria to gain a fuller understanding of the terrorist attack of last week and how we can work together moving forward to combat such threats in the future," Nuland said.

'Blessed operation'
One-eyed veteran Islamist fighter Mokhtar Belmokhtar claimed responsibility for the attack on behalf of al-Qaida.

"We in al-Qaida announce this blessed operation," he said in a video, according to Sahara Media, a regional website. He said about 40 attackers participated in the raid, roughly matching the government's figures for fighters killed and captured.

The fighters swooped out of the desert on Wednesday and seized the In Anema plant and residential barracks nearby.

About 800 people, including some 700 Algerians and 100 foreigners, managed to escape after militants stormed.

Algerian troops launched their first raids on the site on Thursday, but the standoff continued until Saturday, when government forces captured or killed the remaining militants and ended the siege.

According to Salell, the attackers tried to blow up the gas facility on Friday night by planting explosives in a gas pipe and trying to detonate it. The plant produces about 10 percent of the countries gas exports.

The militants demanded an end to French air strikes against Islamist fighters in neighboring Mali that had begun five days earlier. However, U.S. and European officials doubt such a complex raid could have been organized quickly enough to have been conceived as a direct response to the French military intervention.

On Monday, Salell said that a Canadian was one of the coordinators of the attack. Ottawa said it was investigating reports that Canadian nationals were involved.

The siege turned bloody on Thursday when the Algerian army opened fire saying fighters were trying to escape with their prisoners. Survivors said Algerian forces blasted several trucks in a convoy carrying both hostages and their captors.

Nearly 700 Algerian workers and more than 100 foreigners escaped, mainly on Thursday when the fighters were driven from the residential barracks. Some captors remained holed up in the industrial complex until Saturday when they were overrun.

Sellal said negotiating with the kidnappers was essentially impossible.

"Their goal was to kidnap foreigners," he said. "They wanted to flee to Mali with the foreigners, but once they were surrounded they started killing the first hostages."

The bloodshed has strained Algeria's relations with its Western allies, some of whom have complained about being left in the dark while the decision to storm the compound was being taken. Nevertheless, Britain and France both defended the Algerian military action.

"It's easy to say that this or that should have been done. The Algerian authorities took a decision and the toll is very high but I am a bit bothered ... when the impression is given that the Algerians are open to question,'' said French Foreign Minister Laurent Fabius. "They had to deal with terrorists.''

British Prime Minister David Cameron said in a televised statement: "Of course people will ask questions about the Algerian response to these events, but I would just say that the responsibility for these deaths lies squarely with the terrorists who launched this vicious and cowardly attack.

''We should recognize all that the Algerians have done to work with us and to help and coordinate with us. I'd like to thank them for that. We should also recognize that the Algerians too have seen lives lost among their soldiers."

The Islamists' assault has tested Algeria's relations with the outside world and exposed the vulnerability of multinational oil operations in the Sahara.

But physical damage to the gas plant in In Anema was minor, state news service APS reported, citing Oil Minister Youcef Yousfi. The plant would start up again in two days, he said.

Algeria, scarred by the civil war with Islamist insurgents in the 1990s which claimed 200,000 lives, insisted from the start of the crisis there would be no negotiation in the face of terrorism.

France especially needs close cooperation from Algeria to crush Islamist rebels in northern Mali.

Catherine Chomiak, NBC News, Reuters and The Associated Press contributed to this report.

A Canadian national coordinated the Islamist militant attack on a gas plant in Algeria where dozens of foreign workers were taken hostage and at least 37 were slain, Algerian Prime Minister Abdelmalek Sellal told a Monday news conference. 

Sellal said Monday that 37 foreign workers from eight nations had been killed and another five were still missing. He also said 29 militants were killed with three captured alive, Reuters reported.

He was speaking as dramatic stories began to emerge from hostages who escaped the bloody end to the siege at the Tiguentourine plant near In Amenas.

Reuters had reported earlier Monday that an Algerian security source said two of the attackers found dead at the gas plant were Canadian. That report could not be immediately confirmed.

Canadian authorities acknowledged that they were investigating reports of the involvement of at least one of their citizens.

In a statement, Canada's Department of Foreign Affairs said it was "aware of reports that Canadians may have been involved in the hostage-taking in Algeria."

"We are pursuing all appropriate channels to seek further information and are in close contact with Algerian authorities," the statement added. "Canada condemns in the strongest possible terms this deplorable and cowardly attack and all terrorist groups which seek to create and perpetuate insecurity in the Sahel countries of West Africa."

One American, three Britons and two Romanians have been confirmed dead by their home countries and Reuters, citing Japanese government sources, reported that at least nine Japanese nationals also had been killed. An Algerian security source also told Reuters that at least one Frenchman had died.

About 800 people, including some 700 Algerians and 100 foreigners, managed to escape after militants stormed the compound on Wednesday last week.

During Monday's news conference, Sellal provided additional details on the attack, saying the initial objective had been to capture a bus carrying foreign workers and hold them hostage. He also said the attackers tried to blow up the gas facility by planting explosives in a gas pipe and trying to detonate it Friday night.

Algerian troops launched their first raids on the site on Thursday, but the standoff continued until Saturday, when government forces captured or killed the remaining militants and ended the siege.

Among the escaped hostages was Alan Wright, 37, of Scotland, one of 22 Britons who survived the ordeal and were flown back to the U.K. 

'Really bad situation'
Wright told ITV News that he had gone to work as usual Wednesday, but then the power went out.

"We thought it was just a normal shutdown," he said. "Then somebody said, 'There's been a terrorist attack.'"

Wright described gathering food, water and satellite phones and hiding in an office with his co-workers. They huddled there as chaos ensued.

"You could hear gunfire outside, machine-gun fire and mortars and everything going off," he said. "Sometimes rapidly, sometimes quiet for a while, but we knew it was a really, really bad situation."

Echorouk Elyaoumi / AP

Algerian bomb squads scouring a gas plant where Islamist militants took dozens of foreign workers hostage found "numerous" new bodies on Sunday as they searched for explosive traps.

Wright said Algerian employees among the group eventually decided they were better off making an escape attempt.

They provided clothing and hats to help the foreign workers "blend in," he said, and cut a hole in a fence to escape.

They were spotted by Algerian soldiers, who rescued them.

"I'm just delighted to be home," Wright said. "My thoughts now are with my friends and their families who don't know what's happened to their loved ones."

The terrorist monitoring service SITE said Monday that the al-Qaida-linked Mulathameen Brigade, which claimed the mass hostage-taking, threatened to carry out more attacks unless Western powers ended what it called an assault on Muslims in neighboring Mali, Reuters reported.

Reuters and ITV News contributed to this report.

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Expert: Islamists' Algeria raid could inspire copycat attacks

The death toll in the bloody Algeria hostage siege is likely to rise, Algeria warned on Sunday as governments struggled to confirm reports 23 Western workers – including some Americans - had been killed.

A day after the desert crisis was ended by Algerian troops, 25 bodies were discovered inside the gas pumping facility that was stormed by Islamist militants on Wednesday, according to reports cited by Reuters and the Associated Press.

Confusion still surrounds the deadly incident, which has renewed global fears about the likelihood of terror attacks and the safety of Westerners around the world.

It has also left other governments, including Britain, with a frustrating wait for further information out of the west African country.

Algeria’s government said Saturday that 23 hostages and 32 militants were killed during ‘rescue’ assaults launched by its own forces, with 107 foreign hostages and 685 Algerian hostages freed.

However, Minister of Communication Mohamed Said this would rise when final numbers were issued in the coming hours, Reuters reported.

"I am afraid unfortunately to say that the death toll will go up," Said was quoted as saying by the official APS news agency.

The U.S. government confirmed Friday that one of the dead hostages was Frederick Buttaccio from Texas.

The exact number of other Americans involved, and their fate, remains unclear.

President Barack Obama said on Saturday the United States was seeking from Algerian authorities a fuller understanding of what took place, but said "the blame for this tragedy rests with the terrorists who carried it out."

Britain on Sunday confirmed that three of its citizens and one British resident had been killed in the Algerian military operation.

Prime Minister David Cameron echoed Obama’s sentiments, saying responsibility for the deaths “lies squarely with the terrorists who launched the attack,” regardless of questions about the Algerian government's response.

The hostage-taking illustrated the global threat of terrorism which “requires a global response,” Cameron said Sunday.

One Briton had already was confirmed killed when the gunmen seized the hostages before dawn on Wednesday at the plant, run by Norway's Statoil along with Britain's BP and Algeria's state oil company.

The AP reported that "numerous" bodies were found at the pumping facility by Algerian de-mining squads searching for explosives, according to an Algerian government spokesman.

Statoil said five of its workers, all Norwegian nationals, were still missing. Japanese workers are also unaccounted for, Reuters said.

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Details emerge in militant takeover, rescue operation at Algeria gas field

Twenty-three hostages and 32 militants were killed in the attack on a natural gas plant deep in the Sahara, the Algerian interior ministry said on Saturday, according to news services.

The official also said 107 foreign hostages and 685 Algerian hostages had been released, several news outlets reported.

Earlier, British Defense Secretary Philip Hammond said, speaking on information received by the British government, that the hostage crisis had "been brought to an end."

The militants took over the In Amenas plant on Wednesday, but Algeria's military launched a rescue attempt on Thursday.

The Algerian Press Service reported that a during a final attack by Algeria's military, the militants killed seven hostages, whose nationalities were not revealed. All of the remaining militants were reported killed.

At a joint press conference with U.S. Defense Secretary Leon Panetta, Hammond described the loss of life as "appalling and unacceptable."

"We remain in close contact with the Algerian government," Hammond said. "We remain determined to defeat terrorism and stand with the Algerian government."

Hammond said that the latest Algerian military operation had resulted in further loss of life. "We are pressing the Algerians for details on the exact situation and the numbers that have been killed and, if any, the numbers rescued," he said.

The Associated Press reported that around 100 of the 135 foreign workers on the site had been freed by Friday. The U.S. government confirmed Friday that one of the dead hostages was Frederick Buttaccio from Texas.

The 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. 

In a statement Saturday, President Barack Obama said: "The blame for this tragedy rests with the terrorists who carried it out ... This attack is another reminder of the threat posed by al Qaeda and other violent extremist groups in North Africa." 

In a news release Saturday, British Prime Minister David Cameron said he feared for the lives of five British citizens who remained unaccounted for, Reuters reported.

Anis Belghoul / AP

Two British hostages -- Peter, left, and Alan, right (no family name available) -- are seen after being released, in a street near the gas plant where they were kidnapped by Islamic militants.

"One British citizen has already been killed in this brutal attack and we now fear the worst for the lives of five others who are not yet accounted for," Cameron said, according to Reuters.

British Petroleum said Saturday that four of its employees were among the hostages who remain missing.

In a conference call with reporters, Chief Executive Officer Bob Dudley said 14 of the 18 BP employees who were working at the site are “safe and secure” but four remain missing. Dudley said at this time he could not reveal the identities or nationalities of any of the employees. Dudley said the situation remains “very fluid and complex.”

Based on information from those hostages freed, Dudley said they suffered a “terrible and agonizing ordeal” and the situation inside the facility was “horrific.” Before “pre-judging” the actions taken by Algerian security Dudley said “we need he entire picture.”

The In Amenas plant, in a remote part of the Sahara Desert in eastern Algeria close to the Libyan border, is jointly run by BP, Norway's Statoil and Algeria's state-owned oil company.

Reuters and The Associated Press contributed to this report.

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• Details emerge in militant takeover, rescue operation at Algeria gas field

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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Reuters TV

A wounded man is cared for in a hospital in Tigantourine, Algeria, on Jan. 18, 2013 after being freed from Islamist militant captors at a gas field in Algeria.

The militants had filled five jeeps with hostages and begun to move when Algerian government attack helicopters opened up on them, leaving four in smoking ruins. The fifth vehicle crashed, allowing an Irish hostage inside to clamber out to safety with an explosive belt still strapped around his neck.

Three days into the crisis at a natural gas plant deep in the Sahara, it remained unclear how many had perished in the faceoff between Africa's most uncompromising militant group and the region's most ruthless military.

The government said 12 workers, both foreign and Algerian, were confirmed dead. But the extremists have put the number at 35. And the government attack Thursday on the convoy — as pieced together from official, witness and news media accounts —suggested the death toll could go higher. The U.S. government confirmed that one of the dead was a Texan, Frederick Buttaccio.

Meanwhile, the al-Qaida-linked Masked Brigade behind the operation offered to trade two American hostages for two terrorists behind bars in the U.S., including the mastermind of the 1993 World Trade Center bombing — a deal the U.S. rejected out of hand.

The remote In Amenas plant, jointly run by BP, Norway's Statoil and Algeria's state-owned oil company, is deep in the featureless desert. The Algerian government has released few details about the continuing siege.

By Friday, however, the outlines of the takeover by Islamic militants were coming into focus. The attack had been in the works for two months, a member of the Masked Brigade told an online Mauritanian news outlet that often carries al-Qaida-related announcements. The band of attackers included militants from Algeria, Mali, Egypt, Niger, Mauritania and Canada, he said.

He said militants targeted Algeria because they expected the country to support the international effort to root out extremists in neighboring Mali.

Instead of passing through Algeria's relatively well-patrolled deserts, the attackers came in from southern Libya, where there is little central government and smugglers have long reigned supreme, according to Algeria's Interior Minister Daho Ould Kabila.

He said the attackers consisted of about 30 men armed with rocket launchers and machine guns and under the direct supervision of the Masked Brigade's founder himself, Moktar Belmoktar, a hardened, one-eyed Algerian militant who has battled the Algerian government for years and went on to build a Saharan smuggling and kidnapping empire linked to al-Qaida.

Early Wednesday morning, they crept across the border, 60 miles from the natural gas plant, and fell on a pair of buses taking foreign workers to the airport. The buses' military escort drove off the attackers in a blaze of gunfire that sent bullets zinging over the heads of the crouching workers. A Briton and an Algerian, probably a security guard, were killed.

One American killed, 2 escape in hostage crisis, U.S. officials say; two others reportedly still held

Frustrated, the militants turned to the vast gas complex, divided between the workers' living quarters and the refinery itself, and seized hostages, the Algerian government said.

The takeover soon turned into a standoff as military units from a nearby base surrounded the complex.

Algerian TV via Reuters TV

A British man is interviewed by Algerian TV about the In Amenas hostage taking. "I think they did a fantastic job. I was very impressed with the Algerian army,

Algerians interviewed by French radio described militants knocking down doors in the living quarters, saying they were looking for foreigners. The foreign workers, including Americans, Britons, French, Norwegians, Romanians, Malaysians and Japanese, were separated from the Algerians and kept under close guard, wrapped with explosive belts. The Algerians for the most part were allowed to wander freely around the complex, and some were released, according to the state news agency.

Alexandre Berceaux, a Frenchman who was later rescued by Algerian soldiers, described two harrowing days of confusion hiding in his room as Algerian colleagues supplied him with food.

"I stayed hidden in my room for almost 40 hours," he told Europe 1 radio, saying he hid under the bed and didn't even realize when his ordeal was over.

The militants declared that the takeover was prompted by France's attacks on al-Qaida-linked rebels in Mali, and they demanded that the intervention end or the hostages would pay for it.

That night, Kabila, Algeria's top security official, announced that in accordance to Algeria's longstanding policy, "we reject all negotiations with the group." Despite regular elections, Algeria is run by a coterie of generals and ruling party leaders who got the country through a bloody, decade-long Islamist rebellion with brutal tactics that earned them the nickname "the eradicators."

On Thursday afternoon, Algerian military forces saw a five- jeep convoy moving from one part of the complex to another. Fearing the kidnappers were trying to make a break for it, they sent attack helicopters into action.

Irish electrician Stephen McFaul was in that convoy and made it out alive as the world exploded around him.

"Four of the jeeps were taken out and everybody in them was killed," McFaul's brother, Brian, told the Irish Times. "The jeep my brother was in crashed and my brother made break for it," with a belt of explosives strapped around his neck.

The kidnappers called the Mauritanian news service ANI to say that 35 hostages and 15 of their fighters had been killed in the bloodbath — a figure that was impossible to confirm. The kidnappers told ANI that they were just trying to consolidate hostages into a single location when the Algerians attacked.

By Thursday night, the state news agency announced that the assault was over and that special forces had secured the plant, but the next day it would emerge that they had taken only the living quarters. The hostages and their kidnappers remained ensconced in the refinery.

An international outcry mounted over the Algerians' handling of the crisis. Experts noted that this is how they have always dealt with terrorists.

"It's the Russian training for dealing with terrorism," said Matieu Guidere, a longtime expert on al-Qaida and Algeria. "The message is: We will terrorize the terrorists. ... This is clear. The life of hostages is nothing in the balance."

The Algerian government insisted it had to intervene to prevent a catastrophe.

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DIGITALGLOBE/AFP/Getty Images

This satellite image provide by DigitalGlobe from Oct. 8, 2012 shows the In Amenas gas field in Algeria, which is jointly operated by BP, Norway's Statoil and Algeria's Sonatrach.

The audacious assault by Islamist militants on a gas plant in Algeria that led to the capture of scores of hostages could spark copycat attacks, a terrorism expert warned Friday.

Terrorism analyst Evan Kohlmann, an NBC News contributor who has worked for the FBI, said that other groups would almost certainly be watching closely as the militant fighters led by Mokhtar bel Mokhtar seized the giant facility near In Amenas — and might be inspired.

"(Militant groups) are all vying for attention — for fighters, for financing. They see this, they see the attention it gets," said Kohlmann, who has written about the enigmatic bel Mokhtar in the past.

Bel Mokhtar has been called "The Uncatchable" by French intelligence, along with "Mr. Marlboro" due to his reputed cigarette-smuggling empire, and "a jihadist straight out of central casting" by the British press.

"This group has carried out similar attacks to this in the past. They've certainly taken hostages. They've launched attacks against gas fields and mines,"  Kohlmann said.

'Nightmarish scenario'
But what made the In Amenas raid different was the size of the plant and the number of hostages.

"It's the scale here that we're talking about that's astounding. Taking a group like this all at once… It's really… It's a nightmarish scenario, to be honest," Kohlmann said.

"Within the past year, he's given several different interviews and video recordings in which he's been very clear that one of the primary targets for his group are those who are coming to Algeria, Mali, Mauritania and are 'stealing our resources.'"

Kohlmann said an attack on a French uranium mine in Niger in 2010 has been linked to bel Mokhtar’s group. In that case, workers were also kidnapped and four are still being held to this day.

Thursday, the operators of that and another Niger uranium mine, Areva, said they were tightening security after tons of its contaminated metal used in the extraction of uranium were found in a public junkyard.

Bel Mokhtar is a veteran of the Afghanistan war against the Soviets, a conflict in which he reportedly lost his eye, and he was also once in charge of al-Qaida’s Saharan arm.

Algerian TV via Reuters TV

Hostages freed from a gas facility in Algeria, where Islamist militants were holding them, are seen embracing in pictures broadcast by Algerian TV.

But he now runs his own gang, analysts say, and there are suspicions that he is now more interested in money than jihad.

"He fought in Afghanistan. He fought with al-Qaida in Algeria for years. This guy has been fighting in Algeria since 1991. Yet at the same time he's much more of a desert mafioso than anything else," Kohlmann said.

"He espouses jihadi aims. But he's very well-known for smuggling weapons, cigarettes, narcotics and of course these hostage-taking incidents where he's taken a lot of flak, including from within the jihadi community itself," he added.

"Some of them have said, ‘look, you talk about taking people hostage in order to get our prisoners released from jails, but then all you do is take ransom money and you let these people go.' … So, some of them have distanced themselves from him because of his attention and profit-seeking behavior, really," Kohlmann added.

He said he suspected bel Mokhtar was trying "to ingratiate himself to some of these other new jihadi movements in West Africa." 

"And what greater way than to do something like this where not only does he get a lot of media attention, but potentially he makes millions of dollars on ransom payments? And that's what these guys are really motivated by — money," Kohlman said.

Related:

Expert: Islamists' Algeria raid could inspire copycat attacks
Details emerge in militant takeover, rescue operation at Algeria gas field
Violence in Mali, Algeria raises fresh fear of radical Islam
US military cargo planes to help French in Mali
Algerian militant dubbed 'Mr Marlboro' raked in millions from kidnappings
Violence in Mali, Algeria raises fresh fear of radical Islam

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.

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