The UK's prime minister has called an urgent meeting of intelligence chiefs after a British soldier was allegedly killed by two suspected radicals.
UK Prime Minster David Cameron on Thursday convened the meeting of his intelligence chiefs after a British soldier was hacked to death by two men shouting Islamic slogans in a south London street.
A dramatic clip filmed by an onlooker just minutes after the killing showed a man with hands covered in blood, brandishing a bloodied meat cleaver and a knife.
"We swear by almighty Allah we will never stop fighting you. The only reason we have done this is because Muslims are dying every day," the man in his 20s or 30s, wearing a wool jacket and jeans and speaking with a British accent, shouted in the footage obtained by Britain's ITV news channel.
"This British soldier is an eye for an eye, a tooth for a tooth."
The attack was the first apparent radical killing in London since suicide bombers struck transport in July 2005. The capital was shocked by the bizarre scene of a killer covered in gore, declaring his motive to onlookers.
Police shot the two suspects while trying to arrest them, and the wounded men were taken into custody. No information was immediately released about the identity of the suspects, but two sources familiar with the investigation said authorities were investigating a possible link to Nigeria.
"I apologise that women had to witness that, but in our lands our women have to see the same thing. You people will never be safe. Remove your government. They don't care about you," the videotaped man said before crossing the street and speaking casually to the other attacker.
Cameron chairs an emergency national security meeting on Thursday after cutting short a visit to France to return to London.
"The police are urgently seeking the full facts about this case but there are strong indications that it is a terrorist incident," Cameron said before leaving France's President Francois Hollande to return home.
"We have had these sorts of attacks before in our country and we never buckle in the face of them," he said.
The attack happened on the edge of London's sprawling Royal Artillery Barracks in Woolwich, a south London working class district which has long-standing historic links to the military.
In signs of a backlash after the attack, more than 100 angry supporters of the English Defence League, a far-right street protest group, took to the streets, some wearing balaclavas and carrying England's red and white flag. They were contained by riot police.
Separately, two men were arrested in connection with separate attacks on mosques outside London. No one was hurt.
Help for heroes
The authorities did not immediately confirm the identity of the slain man, but a source told Reuters the man may have been a member of the military. The British government normally withholds the identities of slain service members until their families are informed.
The victim was wearing a T-shirt saying "Help for Heroes", the name of a charity formed to help wounded British veterans. Britain has had troops deployed in Afghanistan since 2001 and had troops in Iraq from 2003-2009.
Before he was stabbed to death, the victim was knocked over by a blue car which then rammed into a lamppost. The attackers pounced on him in broad daylight in a busy residential street.
Witnesses said the men shouted "God is greatest" in Arabic while stabbing the victim and trying to behead him.
"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. Police said in a statement that the murder investigation was led by the Counter Terrorism Command, a specialist branch within the London force.
Some onlookers rushed to help the victim and one woman tried to engage one of the attackers in conversation to calm him.
"He had what looked like butcher's tools – a little axe, to cut the bones, and two large knives. He said: 'Move off the body,'" Ingrid Loyau-Kennett was quoted by local media as saying.
"He said: 'I killed him because he killed Muslims and I am fed up with people killing Muslims in Afghanistan.'"
Fred Oyat, a 44-year-old local resident, said he witnessed the attack on the soldier from the window of his high-rise apartment overlooking the scene.
"The victim was white," he told Reuters. "I was in my house when four shots rung out. I went to the window I saw a man lying on the ground with a lot of blood."
London was last hit by a serious militant attack in July 2005, when four young Islamist extremists set off suicide bombs on the public transport network, killing 52 people and wounding hundreds. A similar attempted attack two weeks later was thwarted.
British counter-terrorism chiefs have recently warned that radicalised individuals, so-called "lone wolves" who might have had no direct contact with al-Qaeda, posed as great a risk as those who plotted attacks on the lines of the 2005 bombings.
The bombing attacks on the Boston Marathon last month, which US authorities blame on two brothers, have raised the profile of the "lone wolf" threat in the West. A French-Algerian gunman killed three off-duty French soldiers and four Jewish civilians on a rampage in southern France last year.
Britain's involvement in the wars in Afghanistan and Iraq in the past decade has often stirred anger among British Muslims and occasionally made soldiers a target at home. British police have foiled at least two major plots in which Islamist suspects were accused of planning to kill off-duty troops.
Ahmed Jama, a 26-year-old Woolwich resident, laid flowers down at the scene as a sign of respect to the families involved.
"This has nothing to do with Islam, this has nothing to do with our religion. This has nothing to do with Allah," he said. "It has nothing to do with Islam. It's heartbreaking, it's heartbreaking." – Reuters