A passenger jet heading from Pakistan to England was intercepted by U.K. fighter jets after an "angry passenger" made a bomb threat Friday, an airline official said.

The Boeing 777 was forced to divert from Manchester airport to London Stansted after a disruptive passenger told a flight attendant he would set off a bomb, said a senior Pakistan International Airlines official who asked not to be identified.

"It seems that the threat was passed in anger," the official said. "But we are still trying to figure things out."

The plane, from Lahore, was carrying 308 passengers and landed safely at London Stansted, the official said.

Police said two passengers had been arrested "on suspicion of endangerment of aircraft" - a criminal offense that includes everything from terror threats to misbehavior.

The two passengers who were arrested were identified by Pakistan International Airlines as Safdar Mahmood and Tayyab Subhani, both British nationals. Essex police did not confirm their identities, but confirmed they were British nationals who were ages 30 and 41.

The Royal Air Force Typhoon jets were scrambled after a security alert was sent to air traffic controllers by the passenger jet's pilots, British military officials said. 

They said fighter jets had been scrambled, but the explanation for the alert was not immediately known. 

"Typhoon aircraft from RAF Coningsby were launched today to investigate an incident involving a civilian aircraft within U.K. airspace; further details will be provided when known," the Ministry of Defence said in a statement.

No suspicious items have been recovered from the plane, Essex police said. The plane will remain at its current location for forensic examination by specialists. 

This story was originally published on Fri May 24, 2013 9:14 AM EDT

Ministry of Defence

Drummer Lee Rigby was identified Thursday as the soldier killed in London in a suspected terror attack on Wednesday.

The British soldier brutally killed in London in a suspected terror attack was a drummer in a military band who had served in Afghanistan, officials said on Thursday.

Lee Rigby, 25, known as “Riggers” to his friends, was killed in broad daylight on Wednesday as he walked in Woolwich, South London, near an army barracks.

In a statement, the U.K. Ministry of Defence said Rigby, who served with the 2nd Battalion The Royal Regiment of Fusiliers, was “a loving father” to his two-year-old son Jack.

“An extremely popular and witty soldier, Drummer Rigby was a larger than life personality within the Corps of Drums and was well known, liked and respected across the Second Fusiliers,” the statement said.

“He will be sorely missed by all who knew him. The Regiment’s thoughts and prayers are with his family during this extremely difficult time,” it added. “Once a Fusilier, always a Fusilier.”

The statement said Rigby was born in Manchester, England and had joined the army in 2006.

It said he had been deployed on operation in Helmand province, Afghanistan, in April 2009, “where he served as a member of the Fire Support Group in Patrol Base Woqab.”

Rigby had previously helped guard the U.K.’s royal palaces. “He was an integral member of the Corps of Drums throughout the Battalion’s time on public duties, the highlight of which was being a part of the Household Division’s Beating the Retreat - a real honour for a line infantry Corps of Drums,” the statement said.

He had also served with his unit in Cyprus and Germany. In 2011, Rigby began a recruiting post in London and assisted with duties at the Tower of London.

The commanding officer of the Second Fusiliers, Lieutenant Colonel Jim Taylor, said Rigby was “a dedicated and professional soldier.”

“Larger than life, he was at the heart of our Corps of Drums. An experienced and talented side drummer and machine gunner, he was a true warrior and served with distinction in Afghanistan, Germany and Cyprus,” he said.

His platoon commander from 2010 to 2011, Captain Alan Williamson said “Riggers” was a “cheeky and humorous man, always there with a joke to brighten the mood.”

Related:

• UK mom calms man with blood-soaked knife after suspected deadly terror attack
• PhotoBlog: Britons react with horror and anger to London attack
• 'Leave our lands': Man knifed to death in suspected London terror attack

LONDON - A mother-of-two who confronted a blood-soaked, knife-carrying man in the moments after what is suspected to be the ideologically motivated murder of a British soldier said she wanted to protect onlookers.

Ingrid Loyau-Kennett, 48, jumped off the bus she was riding in southeast London Wednesday when she saw the man slumped on the sidewalk next to a crashed car.

British police said on Thursday that officers from London’s counter-terrorism unit were heading up the investigation. Eyewitness reports suggest the killing may have been carried out as a protest against British military actions in Muslim countries based on what they say they heard from the alleged attackers.

Loyau-Kennett had intended to offer first aid, but instead found herself standing in the aftermath of the horrific killing of a soldier in broad daylight in Woolwich, London.

The U.K. Ministry of Defence named the victim as Lee Rigby, a 25-year-old drummer with the Second Battalion, Royal Regiment of Fusiliers who was father of a two-year-old boy. and who had served in Afghanistan. Floral tributes were laid outside the military barracks near the scene.

“I saw a man on the road obviously injured and a car badly crashed," she told U.K. channel ITV on Thursday. "So I assumed it was a road accident."

However, she says when she got closer she saw a man covered in blood and carrying a butcher's knife. She also says she saw a handgun.

"I thought 'what the heck has happened there?'" she said.

“He was obviously a bit excited and the thing was to talk to him,” Loyau-Kennett said, adding that her instinct was to keep the suspected attacker calm in order to protect the crowd that was beginning to gather.  

ITV News

A suspect, left, talks to the camera immediately after Wednesday's attack.

Pictures at the scene show her, hands in pockets, speaking apparently calmly to a man holding a long knife.

Loyau-Kennett, from Cornwall, England, found it “daunting” to continue to engage the blood-soaked man as more bystanders appeared, in particular mothers with their children.

“There were more and more mothers with children coming by so it was more and more important that I talk to him,” she said.

British Prime Minister David Cameron paid tribute to her Thursday, saying she was "brave" as he pledged that U.K. investigators "will not rest until we know every single detail of what happened and we've brought all of those responsible to justice."

Speaking on the steps of 10 Downing Street, he said: "This country will be absolutely resolute in its stand against violent extremism and terror. We will never give in to terror."

"One of the best ways of defeating terrorism is to go about our normal lives. And that is what we shall all do."

A second alleged attacker, his hands covered in blood and holding a meat cleaver, was captured on video -- obtained exclusively by NBC News's U.K. news partner, ITV News -- telling passers-by: "By Allah we swear by the almighty Allah and we will never stop fighting you until you leave us alone."

Eyewitnesses described the victim of the attack as being chopped up like a "piece of meat."

The witnesses said two men were later shot by officers. The injured duo were taken to a hospital where they were later arrested in connection with the case.

NBC News understands the two suspects have been investigated by British security services in the past.

Two further arrests were made Thursday, Britain's Counter Terrorism Command announced. A 29-year-old man and a 29-year-old woman were taken into custody on suspicion of conspiracy to commit murder. 

The Muslim Council of Great Britain on Wednesday condemned the attack, which it said would "heighten tensions on the streets of the United Kingdom."

"This is a truly barbaric act that has no basis in Islam and we condemn this unreservedly," it said. "Our thoughts are with the victim and his family."

Those tensions were underlined late Wednesday when a small number of members of the anti-immigrant English Defence League extremist group were involved in minor scuffles with police in Woolwich.

In his statement to reporters on Thursday, Cameron said: "This was not just an attack on Britain - and on our British way of life - it was also a betrayal of Islam - and of the Muslim communities who give so much to our country. There is nothing in Islam that justifies this truly dreadful act."

However, on its English-language media Twitter feed, al Qaeda-linked Africa terror group al-Shabab said: "What Cameron describes as a sickening attack is what innocent Muslim woman and children are subjected to every day by British troops."

London Mayor Boris Johnson said it was "completely wrong" to blame the killing on Islam, saying the fault lies with the "warped and deluded" mindset of the people responsible. He said it was "equally wrong" to try to draw any link between the incident and British foreign policy.

He also called on the Londoners to send a message of defiance by carrying on "as normal" in the wake of the horrific attack.

Johnson was speaking to reporters after cycling to a meeting of the British government's emergency response committee, Cobra.

President Obama released a statement on the attack Thursday, condemning it "in the strongest terms."

"The United States stands resolute with the United Kingdom, our ally and friend, against violent extremism and terror.  There can be absolutely no justification for such acts, and our thoughts and prayers are with the family of the victim, the police and security services responding to this horrific act and the communities they serve, and the British people," the president said in the statement.

"Our special relationship with the United Kingdom is especially important during times of trial."

NBC News' Keir Simmons and Rohit Kachroo and ITV News' Darren Burn contributed to this report.

Related:

PhotoBlog: Britons react with horror and anger to London attack

'Leave our lands': Man knifed to death in suspected London terror attack

This story was originally published on Thu May 23, 2013 7:23 AM EDT

Issouf Sanogo / AFP - Getty Images, file

Suicide bombers on Thursday attacked France-owned nuclear giant Areva's uranium mine in Arlit, Niger, seen here on September 26, 2010.

NIAMEY, Niger - Suicide bombers struck a mine run by French nuclear group Areva and a military barracks in Niger on Thursday, killing and wounding several people in separate attacks that underline the widening threat posed by Islamist militants across West Africa.

Military sources said several soldiers were killed in a gun battle with Islamists following a car bomb attack at the barracks in Agadez, the largest town in northern Niger.

Areva said at least 13 members of staff were wounded in another bomb attack at about the same time at the Somair uranium mine it operates in the town of Arlit, in Niger's desert north.

A spokesman for the Niger government, Morou Amadou, said the attacks were by Islamist militants, probably from al Qaeda's north Africa wing, al Qaeda in the Islamic Maghreb (AQIM) or its spin-off West African group The Movement for Unity and Jihad in West Africa (MUJAO), which seized control of neighboring north Mali last year before being ousted by a French-led offensive launched in January.

"These are terrorists who have carried out the suicide attacks in Agadez and Arlit," he said. "The terrorists - I don't know for sure whether it was AQIM or MUJAO - infiltrated these towns and security forces have been deployed and are scouring the area."

The suicide attacks were the first in Niger since the offensive in northern Mali drove Islamist groups there into the vast, empty desert and across borders into neighboring Sahel states.

The Niger army has deployed as part of a West African force in Mali. Islamist suicide bombers have carried out a spate of attacks there in recent months, including one on a Niger army barracks earlier this month.

Military sources in Agadez said a suicide bomber drove a truck through the barrier of the town's military base before dawn on Thursday and detonated his explosives when soldiers opened fire.

"The suicide bomber was not alone: There were other terrorists who followed in cars and there were clashes," said one of the military sources, who said there were several dead on both sides. "The situation is now under control."

A Western diplomat, who asked not to be identified, said at least 10 people had been killed in the attack.

Areva said in a statement issued in Paris that at least 13 members of staff were wounded in the attack on its Somair mine.

The company said security at the site was being handled by the Niger military, though French sources had recently said Paris planned to send special forces to the area for extra protection.

"The group condemns this odious attack against its staff," Areva said. "We express our solidarity with the government and the people of Niger in this common trial."

Niger's armed forces have taken part in recent weeks in a joint operation against Boko Haram Islamists in the Nigerian town of Baga on the shore of Lake Chad, in which dozens of people were reported killed.

Nigeria, to the south, again asked its neighbor for military aid this week, after President Goodluck Jonathan declared a state of emergency in three northern states and launched an offensive against Boko Haram insurgents.

Nigeria worries that the four-year-old insurgency based in its remote northeast is being fed from abroad, through Niger, Chad and Cameroon. 

Related:

• Why France is taking on Mali extremists
• After Algerian incident, West Africa fears Mali spillover
• Al Qaeda-linked militants planned attack on US Embassy in Egypt

This story was originally published on Thu May 23, 2013 7:17 AM EDT

LONDON -- A man was killed by knife-wielding assailants on a London street Wednesday, and a bloodstained suspect at the scene holding a meat cleaver was captured on video telling passers-by: "We swear by the almighty Allah."

Eyewitnesses said the two attackers were later shot by officers, and described the victim as being chopped like a "piece of meat." Those two men were taken to a hospital where they were later arrested.

Local lawmaker Nick Raynsford said the dead man was a British soldier serving at a nearby barracks, but the Ministry of Defence could not immediately confirm this.

The man holding the cleaver was videotaped by a bystander saying: "By Allah we swear by the almighty Allah and we will never stop fighting you until you leave us alone."

In the video, obtained exclusively by NBC's UK news partner, ITV News, the man also said: "Leave our lands and we can all live in peace, that's all I have to say."

Prime Minister David Cameron, on a trip to Paris which he cut short to return to London and chair an emergency national security meeting, said: "It is the most appalling crime. Tonight our thoughts should be with the victim and their families and friends.

"People across Britain, people in every community, I believe, will utterly condemn this attack. We have had these sorts of attacks before in our country and we never buckle in the face of them.

"In a free country, the best way to defeat terrorism is to live your life, to show that terrorists can never win."

The two suspects were being treated at separate London hospitals, police said.

A senior British security source said it appeared to be an "ideologically motivated" killing. "From the look of it, it is indeed a low-tech terror attack," the source said.

"I am afraid it is overwhelmingly likely now to be a terrorist attack, the kind the city has seen before," London mayor Boris Johnson said in televised remarks.

The Muslim Council of Great Britain condemned the killing, which it said "will no doubt heighten tensions on the streets of the United Kingdom."

"This is a truly barbaric act that has no basis in Islam and we condemn this unreservedly," it said. "Our thoughts are with the victim and his family."

A witness identified as James told local radio station LBC that he saw two suspects attack the young victim with knives, including a meat cleaver.

"They were hacking at this poor guy, literally," he told the station. "They were hacking at him, chopping him, cutting him."

Multiple witnesses said the victim was wearing a T-shirt bearing the logo of the veterans charity Help for Heroes.

The attack took place less than a mile from a military barracks, in Woolwich, southeast London.

Britain’s Home Secretary Theresa May told ITV News she had been briefed by the Director General of the Security Service MI5 on what she called a "sickening and barbaric" attack.

One eyewitness posted on Twitter that he had seen the victim "with his head chopped off" but this was not confirmed by any police or government officials.

Local resident Graham Wilders told the BBC he saw a man pulling out a handgun. He said: 

“As I drove around the corner I see the car on the pavement. I thought there’s been an accident … there was two people leaning over and I thought they were trying to resuscitate him, there was a bloke against the wall.

“Next minute ... another bloke has come along and told me they were actually stabbing him, apparently they actually run the car into him and knocked him down before they done anything.

“And then next minute there was a bloke come along in a silver little car and he got out and he shouted out to everyone ‘someone phone the police.’ So we phone the police. So next minute what happened he actually pulled a handgun out.”

“Next minute I see the silver car shoot off.”

Metropolitan Police Commander Simon Letchford told reporters there were "a number of weapons" used in the attack, including a firearm. 

The attack happened at 2:20 p.m. local time (9:20 a.m. ET), he said. The attackers pounced on the victim in broad daylight.

After making his statement in the video (seen below), the man with the bloody knives walked back to the scene and spoke to the other suspect casually. 

Meanwhile, the New York Police Department on Wednesday said it had increased coverage of the British consulate, military recruiting stations and other locations as a result of the British attack. But department spokesman Paul Browne said those moves were not made based on information those facilities had been targeted, but rather in an abundance of caution.

NBC News' Richard Esposito contributed to this report

This story was originally published on Wed May 22, 2013 5:49 PM EDT

An al Qaeda-linked cell disrupted in Egypt was planning suicide attacks on the French and U.S. embassies, the state news agency MENA reported, according to Reuters.

In light of this news and last week’s stabbing of a U.S. citizen on the embassy’s perimeter, the U.S. Embassy in Cairo alerted U.S. citizens to exercise “elevated awareness.”

“The knife attack on the Embassy's perimeter, along with weekend media reports acknowledging that Egyptian authorities have disrupted a terror cell possibly targeting Egyptian and Western interests, serve as yet another reminder of the need to exercise good situational awareness,” read a statement from the embassy, which was obtained by NBC News. 

According to Reuters, authorities announced Saturday they had captured three Egyptians with al Qaeda links, saying they had been found in possession of 22 pounds of explosive materials.

"The investigations revealed that the suspects were intending to carry out terrorist bomb operations inside Egypt via suicide operations, penetrating the security cordon in front of the American and French embassies with a car bomb," MENA said, citing a source in the state security prosecutor's office, according to Reuters.

MENA said the suspects had escaped from prison in 2011, during the revolts that removed Hosni Mubarak from power.

Reuters contributed to this report.

This story was originally published on Wed May 15, 2013 2:33 PM EDT

Tobin Jones / AMISOM via AFP - Getty Images

A Somali dock worker carries cement unloaded from a ship to a waiting truck at Mogadishu's main port. The aid effort in the war-torn country is shifting toward boosting the economy amid claims it now has a "bright future."

Somalia has long been defined by terrorism, famine, and piracy.

But as the United States this week pledged another $40 million towards its recovery, Somalia's leaders said the country had finally turned a corner in the fight against the al Qaeda-linked militant group, al-Shabab.

“A bright future for Somalia is within touching distance,” Prime Minister Abdi Farah Shirdon proclaimed on Twitter as the U.S. attended a global summit in London to discuss the country’s future.  

Organizers of the conference sought to build upon the new normality creeping into the nation’s capital, Mogadishu. The country that is often referred to as "the world's most dangerous" is not as dangerous as it once was.

Pirates have not successfully hijacked any ships off Somalia's coast in almost a year and a growing sense of security and confidence has been fueled by the relative retreat of al-Shabab, which controlled much of the country until Kenyan forces invaded in 2011.

Somalia is a battleground not only for its own rival factions, but also for the U.S. and its allies in the fight against al Qaeda, which is opening up Africa as a new global front line.

U.K. Prime Minister David Cameron said the international community should be careful to avoid Somalia becoming a hotbed for radicalism.

"If we ignore it, we will be making the same mistakes in Somalia that we made in Afghanistan in the 1990s. I'm not prepared to let that happen," he told the summit on Tuesday. 

To that end, the U.S. has pumped more than $1.5 billion worth of assistance into the country since 2009, including the $40 million pledged on Tuesday. It is among the countries pledging aid in the hope that stability will encourage security.

The fall of dictator Mohamed Siad Barre in 1991 left Somalia without effective central government and awash with weapons.

But there are signs of fragile progress. Airplanes flying in from neighboring Kenya are filled with members of the diaspora returning home after being forced out by hunger and civil war.

Last year, Turkish Airlines decided to start a commercial service from Istanbul. Officials in Mogadishu hope that the city’s beaches might one day attract a significant number of tourists on those flights. 

But Somalia’s renaissance has limits. Mogadishu is still considered too dangerous to host a meeting of world leaders and senior government officials.

Although al-Shabab has been pushed to the outskirts of the capital by foreign peacekeepers, it maintains the ability to strike at its heart.

Mohamed Abdiwahab / AFP - Getty Images

Security surround the area following a suicide attack on a government convoy in Mogadishu on May 5. Around 11 people were killed.

It proved its deadly potential on April 14 when terrorists attacked Mogadishu’s courthouse. A deadly car bomb was detonated in the center of the city a month earlier. On Sunday, a suicide bomber rammed an explosives-laden car into a convoy carrying Qatari officials, killing at least eight Somalis.

Ahmed Soliman, research assistant at British think tank Chatham House, believes such attacks will become more frequent as al-Shabab tries to disrupt areas it no longer controls.

“Al-Shabab still controls the majority of rural and south-central areas of Somalia,” he said. “The shift toward insurgent attacks could be a sign of weakness – that it has been forced to change tactics and attack areas that it no longer dominates.  But I think it could also play a game of cat-and-mouse with foreign troops by trying to make gains in northern areas just as the troops establish control in south-central areas.”

“It is being kept at bay by international forces under AMISOM [the African Union Mission in Somalia] but that will only last as long as those forces are there. Things are undoubtedly changing, but the jury is still out on whether al-Shabab has been defeated.”

Abdulhakim Haji Faqi, Somalia's defense minister, said his country's forces desperately need military resources. 

"In order to win this war against al-Shabab, we need to get the proper equipment," he said. "We are not asking for air forces, we are not asking for ships, we are not asking for huge military equipment, we are asking only for light weapons and ammunition so that our soldiers can effectively fight."

He added that this was an "international issue," not just a problem for Somalia as extremists from Pakistan, Yemen and Afghanistan -- as well as the U.S., Canada and Britain -- had been operating in the country.

"International organizations based in Somalia are trying to attack neighboring countries in the region and are also trying to cause international problems elsewhere," he said. 

Somalia’s fledgling U.N.-backed government, which took power in September after more than a decade of transitional rule, insists things are looking up – but admits the process will take time.

“Somalia is a country that has been exposed to anarchy for over two decades,” President Hassan Sheikh Mohamud told the U.K.’s Sunday Telegraph newspaper in an interview ahead of the summit. “When I was elected I was attacked within two days, and there were suicide bombers in every corner of my hotel. There are threats against me all the time.”

“There is a huge amount at stake in Somalia: the future of this country, the security of the region, the removal of the piracy stranglehold," he added.

The sharp reduction in attacks on commercial ships off East Africa has been driven by a government amnesty for young pirates backed by international military patrols.

Slideshow: Famine strikes East Africa

Dai Kurokawa / EPA

Somali refugees are seeking shelter in Mogadishu and Kenya from extreme drought and hunger in what the UN's refugee agency is calling the worst humanitarian disaster in the world.

Launch slideshow

“As long as the international naval presence remains, piracy rates will stay low,” said Adjoa Anyimadu, research associate at Chatham House.  “It’s impressive how much countries have worked together to provide naval protection - China and Russia are among those working in the U.S.-led operation.”

In another potential sign of recovery, Deputy U.N. Secretary-General Jan Eliasson wants to shift aid efforts away from away from humanitarian aid and toward development projects. The U.N. estimates Somalia will need $1.33 billion this year.

The country still faces desperate poverty. More than 200,000 children under 5 are acutely malnourished, and just under half of Somalis live on less than $1 a day.

Millions still live in refugee camps, and that country lacks government structures such as schools, hospitals and sanitation.

"The main reason we have hope now, more than ever .... is we now have a leadership which has a sense of responsibility," Eliasson told Reuters on Tuesday.  "The trend is positive, but it has been interrupted, and it might still be interrupted by sporadic attacks of the nature we have seen. Al-Shabab are still a threat.”

Al-Shabab is blamed not only for causing instability across the Horn of Africa, but for contributing to the famine that struck Somalia between 2010 and 2012. According to a report released last week by the U.S.-funded famine early warning system (FEWSNET) and the United Nations, more than a quarter of a million people died during the crisis.

A peaceful solution to these problems is far from likely. Al-Shabab remains an attractive organization to many in country where youth unemployment is running at about 70 per cent. “Al-Shabab pays its fighters and gives them food,” Soliman noted.

“Several of its commanders are high on the list of the U.S. government list of most wanted terrorists,” so direct peace talks are off the agenda, Soliman said. However, unofficial meetings with Somalia’s government are possible.

There are also problems with the country’s own forces. In a report published Monday, Human Rights Watch said it had documented “serious abuses” by Somali security forces, including the army, police, intelligence agencies, and government-affiliated militia.

“Abuses documented include murder, rape, torture, arbitrary arrest and detention, and looting,” the report said. “These abuses were committed with almost complete impunity.”

However, Somalia’s president remains committed to the task ahead. “One thing is very clear…that Somalia is fragmented into pieces,” Mohamud said. “Reversing all that has been happening in the past two decades is a very tedious work that requires some time.”

NBC News' Michele Neubert and Alastair Jamieson and Reuters contributed to this report.

Related:

DUBAI - The United Arab Emirates said on Thursday it had arrested a seven-member group linked to al Qaeda that was planning actions against the Gulf Arab oil exporting country's security. 

State news agency WAM said the members were of various Arab nationalities and had been recruiting, financing and providing logistical support to al Qaeda. They had also sought to expand their activities to other countries in the region, WAM said. 

"The cell was planning actions that would target the country's security and the safety of its citizens and residents, and was carrying out recruitment, and promoting the actions of al Qaeda," WAM said. 

"It was also supplying it [al Qaeda] with money and providing logistical support and seeking to expand its activities to some regional countries," WAM said. 

The United States-allied UAE, a federation of seven emirates and a major trading hub that has supported Western efforts to counter militancy in the region, has been spared any attack by al Qaeda and other insurgency groups.

But some of its emirates have seen a rise in Islamist sentiment in recent years. 

In December the UAE said it had arrested a cell of UAE and Saudi Arabian members of a "deviant group" that was planning to carry out militant attacks in both countries and other states. The phrase "the deviant group" is often used by authorities in Saudi Arabia to describe al Qaeda members. 

There was no immediate word on whether the December arrests were related to those announced on Thursday. Diplomats in the region have said the December arrests were related mostly to Islamist activity in Yemen. 

In 2010, Al Qaeda in the Arabian Peninsula (AQAP), a merger of al Qaeda's Yemeni and Saudi branches, said it was behind a plot to send two parcel bombs to the United States. The bombs were intercepted in Britain and the UAE emirate of Dubai. 

The United States has poured aid into Yemen to stem the threat of attacks from AQAP and to try to prevent any spillover of violence into Saudi Arabia, the world's top oil exporter. 

In August 2012, Saudi authorities arrested a group of suspected al Qaeda-linked militants - mostly Yemeni nationals - in Riyadh. 

Saudi Arabia has arrested thousands of suspected militants since attacks between 2003 and 2006 on residential compounds for foreign workers and on Saudi government facilities in which were dozens of people were killed. 

Related:

Report: US democracy workers detained in UAE

LONDON -- British authorities ordered more police on the streets for Sunday's London Marathon in the wake of the Boston bombings, but experts warned it was "virtually impossible" to guarantee the safety of the hundreds of thousands who will attend the event. 

A police source said additional patrols by uniformed officers were planned to reassure the public in the wake of deadly attack.

While British security officials have been in contact with their counterparts in the U.S. following Monday's blasts, the U.K.'s threat level for international terrorism hasn't been changed from "substantial" -- the third of five categories on the scale.

At least 500,000 spectators are expected to watch Sunday’s race and Prince Harry is due to hand medals to the winners.

The course takes the 36,000 runners right past major sites - including Tower Bridge, the Houses of Parliament and Buckingham Palace – as well as through Canary Wharf, the giant riverside financial district targeted twice by the Irish militants in the 1990s.

Even in a city that has spent recent decades under the threat of bombs – first from Irish Republicans, more recently jihadists – such a public event poses a security headache.

Sir Bernard Hogan-Howe, the commissioner of London's Metropolitan Police, said that the force was "taking more more precautions than we might have done otherwise."

"We will make sure we've got more officers on the street looking after people, making sure they're kept safe, but we've no reason to think they'd be any less safe than before the terrible events in Boston,." he said. "We'd be professionally irresponsible if we didn't take some reasonable steps."

Sang Tan / AP

Backdropped by Buckingham Palace, a jogger crosses the Mall in London on Tuesday. It will be transformed into the finishing area for Sunday's London Marathon.

Metropolitan Police Commander Christine Jones declined to give details of what changes might be made, if any, to the event's security plan. She said officers would “continue to review all the intelligence” available.

London Marathon chief executive Nick Bitel insisted the event would go ahead. “We will be reviewing our security in the coming days, in the light of what has happened in Boston," Bitel told ITV News.

"I don't want to talk about specifics of what security we have had in the past, or will have on Sunday. All I can say is that it will be of an appropriate level to meet whatever threat assessment is made, in conjunction with the police," he added.

Hugh Robertson, a British government minister, called for crowds and runners to attend in London as normal.

“The very best way to show solidarity with Boston is to get out there on the streets of London to cheer the runners on and to show that we won’t be defeated by this sort of activity,” he told the London Evening Standard newspaper.

Runners will be encouraged to wear a black ribbon at the start of the race to honor victims of the Boston bombing, and a 30-second silence will be observed, organizers said Wednesday. 

NBC News national security analyst Michael Leiter said it was “virtually impossible” to make a marathon completely secure because of its 26.2-mile long route.

“You just have to do the best you can to keep people safe and maintain resilience," he said. “It’s important we don’t alter our lives because that provides the terrorist – domestic, international, whoever it may be – with a huge victory.”

Helmut Spahn, executive director of the International Centre for Sport Security, told Reuters: "There has to be a clear analysis of the situation and certainly no over-reaction. More police, more military is not always the best solution. To have a 100 percent security is very, very difficult if not near impossible.”

Sang Tan / AP

A sign warns of road closures linked to the forthcoming London Marathon.

This story was originally published on Wed Apr 17, 2013 2:29 AM EDT

ALGIERS, Algeria -- Fifteen hostages were reported Thursday to have escaped from Islamist fighters who claimed to be holding 41 foreign nationals after taking over a gas plant in the Algerian desert.

U.S. officials said Wednesday that three Americans were among the hostages, but the report of the escape by Algerian television did not make clear whether they were among those who managed to flee.

Mauritania's ANI news agency reported that one of the kidnappers had claimed two Algerian army helicopters attacked the gas complex, injuring two of the Japanese hostages. It was not possible to independently verify the report, Reuters said. ANI has close contacts with the al-Qaida-linked group that has claimed responsibility for the mass kidnapping.

Nearly 24 hours after gunmen stormed the natural gas pumping site and workers' housing before dawn on Wednesday, little was certain beyond a claim by a group calling itself the "Battalion of Blood" that it was holding foreign nationals, including Japanese and Europeans in addition to the Americans, at Tigantourine, near In Amenas, deep in the Sahara.

The raid opened an international front in the civil war in neighboring Mali, just as French troops launched an offensive against Islamist rebels in that country.

Kjetil Alsvik / Statoil via AFP - Getty Images, file

This picture released by Norway's Statoil on shows vehicles parked at the In Amenas gas field in eastern Algeria near the Libyan border. Algerian troops surrounded Islamists holding foreign hostages at the field on Thursday.

On Wednesday, Defense Secretary Leon Panetta said he wanted "to assure the American people that the United States will take all necessary and proper steps that are required to deal with this situation."

British Foreign Secretary William Hague confirmed one Briton had been killed and "a number" of others were being held hostage. Algerian media said an Algerian was killed in the assault. Another local report said a Frenchman had died.

"This is a dangerous and rapidly developing situation," Hague told reporters in Sydney on Thursday, adding Britain's Prime Minister David Cameron had spoken with the Algerian President Abdelaziz Bouteflika.

The crisis presents French President Francois Hollande with a daunting dilemma and spreads fallout from Mali's war against loosely allied bands of al-Qaida-inspired rebels far beyond Africa, challenging Washington and Europe.

Led by an Algerian veteran of guerrilla wars in Afghanistan, the group demanded France halt its week-old intervention in Mali, an operation endorsed by Western and African allies who fear that al-Qaida is building a haven in the desert.

Hollande has warned of a long, hard struggle in Mali and now faces a risk of attacks on more French and other Western targets in Africa and beyond.

The Algerian government ruled out negotiating and the United States and other Western governments condemned what they called a terrorist attack on a facility, now shut down, that produces 10 percent of Algeria's gas, much of which is pumped to Europe.

A French businessman with employees at the site said the foreigners were bound and under tight guard, while local staff, numbering 150 or more, were held apart and had more freedom.

The militants, communicating through established contacts with media in neighboring Mauritania, said they had dozens of men at the base, near the town of In Amenas close to the Libyan border, and that they were armed with mortars and anti-aircraft missiles.

The group said its fighters had rigged explosives around the site and any attempt to free the hostages would lead to a "tragic end."
Algerian Interior Minister Daho Ould Kablia said the raid was led by Mokhtar Belmokhtar, who fought Soviet forces in Afghanistan in the 1980s and recently set up his own group in the Sahara after falling out with other local al-Qaida leaders.

Belmokhtar is a holy warrior and smuggler dubbed "The Uncatchable" by French intelligence and "Mister Marlboro" by some locals for his illicit cigarette-running business.

In their own statements, the militants condemned Algeria's secularist government for "betraying" its predecessors in the bloody anti-colonial war against French rule half a century ago by letting French warplanes fly over its territory to Mali. They also accused Algeria of shutting its border to Malian refugees.

Hollande has called for international support against rebels who France says pose a threat to Africa and the West, and admits it faces a long struggle against well-equipped fighters who seized Timbuktu and other oasis towns in northern Mali and have imposed Islamic law, including public amputations and beheading.

Islamists have warned Hollande that he has "opened the gates of hell" for all French citizens.

The conflict, in a landlocked state of 15 million twice the size of France, has displaced an estimated 30,000 people and raised concerns across mostly Muslim West Africa of a radicalization of Islam in the region.

NBC News' Robert Windrem contributed to this report.

Related stories:

French to send 1,000 more troops to Mali; US playing supporting role
ANALYSIS: Why France is taking on Mali extremists
Al-Qaida-linked fighters destroy 'end of the world' gate in Timbuktu