By Guy Faulconbridge and Michael Holden
LONDON, May 23 (Reuters) - British authorities have established that one and possibly both of the men who hacked a soldier to death on a London street was born in Britain of Nigerian descent, a source with knowledge of the investigation said on Thursday.
Local media named the man who was definitely born in the country as 28-year-old Michael Adebolajo and said police raided the home of his Nigerian family in a village near the eastern English city of Lincoln. Both men appeared to have converted to Islam from Christian immigrant backgrounds, British media said.
Both suspects in the attack, conducted in broad daylight on Wednesday afternoon, are in custody after being shot by police.
As security experts highlighted the risk to Western cities of "lone wolf" attacks by local people radicalised over the Internet, Prime Minister David Cameron held an emergency meeting of his intelligence chiefs to assess the response to what he called a "terrorist" attack, the first deadly strike in mainland Britain since local Islamists killed dozens in London in 2005.
"We will never give in to terror or terrorism in any of its forms," Cameron said outside his Downing Street office.
"This was not just an attack on Britain and on the 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."
The two men used a car to run down the still formally unidentified soldier near Woolwich Barracks in southeast London on Wednesday afternoon and attempted to behead him with a meat cleaver and knives, witnesses said, before telling bystanders they acted in revenge for British wars in Muslim countries.
A dramatic clip filmed by an onlooker showed one of the men, in his 20s and casually dressed, his hands covered in blood and speaking in a local accent apologising for taking his action in front of women but justifying it on religious grounds:
"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," he said. "This British soldier is an eye for an eye, a tooth for a tooth."
The attack, just a month after the bomb attacks on the Boston Marathon, revived fears of "lone wolves". These may have had no direct contact with al Qaeda but are inspired by radical preachers and by Islamist militant Web sites, some of which urge people to attack Western targets with whatever means they have.
Chilling images of the blood-soaked suspect - who urged Britons to overthrow their government or risk having their children face a fate similar to a dead soldier lying just yards away - were splashed across the front pages of newspapers.
"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 man said in the video before crossing the street and speaking casually to the other attacker.
Police said they searched a house in eastern England believed to be the home of the father one of the attackers.
The grisly attack took place 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.
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 lamp-post. The attackers pounced on him in broad daylight in a busy residential street.
Witnesses said they shouted "Allahu akbar" - Arabic for God is greatest - while stabbing the victim and trying to behead him. A handgun was found at the scene.
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.'"
'HELP FOR HEROES'
London was last hit by a serious militant attack on July 7, 2005, when four young Islamists set off suicide bombs on the public transport network, killing 52 innocent people and wounding hundreds. A similar attempted attack two weeks later was thwarted.
In 2007, two days after police defused two car bombs outside London nightclubs, two men suspected of involvement, a British-born doctor of Iraqi descent and an Indian-born engineer, rammed a car laden with gas into the Glasgow Airport terminal, setting it ablaze. One of the attackers died and the other was jailed.
Britain has long known political violence on the streets. In 2009, two British soldiers were shot dead outside a barracks in Northern Ireland in an attack claimed by Irish republicans.
Since the 2007 bombings, known as 7/7, security chiefs say they have faced at least one plan to carry out an attack on the level of the 2005 attacks and have warned that radicalised individuals posed a grave risk to national security.
Peter Clarke, the former head of London's Counter Terrorism Command who led the investigation into the 7/7 bombings, said that if the Woolwich attackers did turn out to be acting alone, it showed the difficulty the security services faced in trying to stop them.
"An attack like this doesn't need sophisticated fund raising and sophisticated communications or planning," he told Reuters. "It can be organised and then actually delivered in a moment."
The bombing attacks on the Boston Marathon last month, which U.S. 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 members of the military.
Cameron's office officials had welcomed the condemnation from most mainstream British Muslim groups but that the national security committee had discussed community cohesion.
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 on Wednesday, 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.
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." (Additional reporting by Peter Griffiths; Writing by Guy Faulconbridge and Maria Golovnina; Editing by Peter Graff and Alastair Macdonald)