Timeline of British Islamist attack

-- 2:20pm. Police receive an emergency call stating that a man was being attacked by two other men in a street in Woolwich, southeast London. Later calls report the use of firearms.

Police officers and ambulance services are dispatched, although the victim is already dead.

-- 2:34pm. An armed response unit arrives. Police fire their weapons and the two suspects are wounded. One of the men is airlifted to hospital by helicopter, the other is taken by ambulance.

-- As news of the incident breaks onto the national media, local MP Nick Raynsford said the victim was thought to be a serving soldier. Witnesses later say he was wearing a t-shirt bearing the logo of Help for Heroes, a military charity.

-- A distressed eyewitness, who identified himself only as James, tells London's LBC Radio that he saw two black men in their 20s hacking at a young man like he was "a piece of meat".

"They were just animals. They dragged him from the pavement and dumped his body in the middle of the road and left his body there," he said.

He said the two men stood around apparently waiting for the police to come. They even asked people nearby to take pictures of them.

When the armed police officers arrived, he said the men "charged at the police vehicle" and the other man fired a shot.

Another witness, Graham Wilders, said he had heard that the attackers had run over the soldier and knocked him down before stabbing him. One of the suspects had a handgun.

"These men actually went for the police with the machetes, knife and handgun. I don't think they cared," he said, adding: "The police were the only ones who did any shooting."

-- Media reports suggest the government is treating the murder as a terror incident, and quote sources suggesting it may have been deliberately filmed and that at least one of the attackers shouted "Allahu Akbar", Arabic for "God is great".

-- Shocking footage emerges at approximately 6:30pm of one of the apparent suspects, a young black man who has blood on his hands and is holding a bloody kitchen knife and a meat cleaver.

"We swear by the almighty Allah we will never stop fighting you until you leave us alone," he says. "We must fight them as they fight us. An eye for a eye and a tooth for a tooth."

-- 6:39pm. Prime Minister David Cameron's office says he is cutting short his trip to Paris to return to London and has asked the interior minister to chair in his absence a meeting of COBRA, the government's emergency committee.

-- 7:15pm: A Buckingham Palace spokesman says Queen Elizabeth II, due to visit the military barracks near the attack site on May 31, is "concerned" and is being kept informed.

-- 7:18pm. Cameron condemns the "barbaric attack" at a press conference in Paris, saying: "There are strong indications that it is a terrorist incident."

-- 7:55pm: Home Secretary Theresa May says security has been stepped up in army barracks across London.

-- Around 10:00pm: About 250 supporters of the far-right English Defence League group gather at Woolwich Arsenal train station near the murder scene in a protest against Islam. They briefly clash with police.

-- 9:00am: Cameron chairs another meeting of COBRA attended by national security chiefs.