UPDATE: The name of the victim and one of the suspects has been released. From the BBC:
The soldier killed in an attack in London has been named as Drummer Lee Rigby of the 2nd Battalion the Royal Regiment of Fusiliers.
Drummer Rigby, 25, from Manchester, leaves behind a two-year-old son.
Two suspects shot by police after Wednesday's attack in Woolwich remain under arrest. A further two people have been arrested on conspiracy to murder.
The suspects, one of whom is said to be Islamist protester Michael Adebolajo, were known to security services.
UPDATE: Here is footage of the suspected killer speaking to passerby moments after the killing. WARNING: Highly disturbing images
From the Independent:
A man believed to be a soldier has been beheaded in an attack on a street near the Woolwich barracks in London, witnesses report.
Metropolitan Police Commander Simon Letchford confirmed tonight that two men were shot by armed officers.
Exclusive ITV footage shows that one man was filmed wielding a bloodied meat cleaver and saying: "We swear by almighty Allah we will never stop fighting you."
He adds: "We must fight them as they fight us. An eye for an eye, a tooth for a tooth. I apologise that women have had to witness this today, but in our land our women have to see the same. You people will never be safe. Remove your government, they don't care about you."
Prime Minister David Cameron has described the killing as "truly shocking" and has asked the Home Secretary Theresa May to chair a meeting of Cobra, the Government's emergency committee dealing with incidents that have implications for national security. He is returning to London early from an EU meeting.
Reports the BBC:
The Guardian has an eyewitness account of the murder:
Julia Wilders,51, a local resident, said that she saw a car had crashed into a lamppost when she went to investigate. "My husband said there's two people trying to resuscitate someone. We parked and walked back to have a look and all of a sudden a tall black bloke come up with a gun. My husband said, 'Get back, get back' and we called the police."
She said that one man was dressed all in black with a black cap whilst the other was dressed in a green jumper."They looked like they were on drugs," she said.
She said the black hand gun was pointed down and a crowd soon gathered.
Her husband Graham, 50 called the police to alert them to what they believed was an accident.
"After we called the police I went over to the school to let the school know so the kids wouldn't come out," she said.
"I walked back up there and the tall black bloke had changed the gun to the other guy and he had two meat cleavers in his hand. And the response police turned up and he's ran towards them with meat cleavers before I could even get out of the car so they shot him. And then the other one lifts the gun up and they shot him as well.
She did not know how many shots the police fired but said both assailants fell to the ground after being hit.
She didn't believe the assailants weapons were fired. "He looked like he was going to, sort of like he was going to lift it up towards the police."
Her husband said that it looked like the two men were trying to revive the man they'd run over. "They looked like they were pumping his chest but they said that they were trying to cut his head off."
"A guy in a car told people to ring 999 and then taller guy started waiving the gun at him."