A mother confronted the Woolwich attackers, asking them to hand over their weapons and warning them: "It is only you versus many people, you are going to lose", it has been reported.
Ingrid Loyau-Kennett, 48, told the Daily Telegraph that one of the attackers said to her that they "want to start a war in London tonight".
The mother-of-two, a cub scout leader from Cornwall according to the report, added: "Being a cub leader I have my first aid so when I saw this guy on the floor I thought it was an accident - then I saw the guy was dead and I could not feel any pulse. And then when I went up there was this black guy with a revolver and a kitchen knife, he had what looked like butcher's tools and he had a little axe, to cut the bones, and two large knives, and he said 'move off the body'."
She continued: "So I thought 'OK, I don't know what is going on here' and he was covered with blood. I thought I had better start talking to him before he starts attacking somebody else. I thought these people usually have a message so I said, 'what do you want?' I asked him if he did it and he said yes, and I said: 'Why?' And he said because he has killed Muslim people in Muslim countries, he said he was a British solider and I said, really? And he said: 'I killed him because he killed Muslims and I am fed up with people killing Muslims in Afghanistan, they have nothing to do there.'"
Mrs Loyau-Kennett said that the attacker seemed to be "in full control of his decisions and ready to do everything he wanted to do." She added: "I said, 'Right now it is only you versus many people, you are going to lose, what would you like to do?' and he said: 'I would like to stay and fight.'"
Other eyewitnesses described seeing the "crazed" Woolwich attackers "hacking" at their victim and posing for pictures before charging at police wielding meat cleavers. One onlooker, identified as James, said he saw two black men chopping at a man in his 20s like he was "a piece of meat". He told LBC radio: "They were hacking at this poor guy, literally. They were hacking at him, chopping him, cutting him."
Describing the murderers as "animals", he told how he saw them drag their victim from the pavement into the middle of the road. "These two guys were crazed," he said as he fought back tears.
The witness added that they then stood around, waving knives and a gun, asking people nearby to take pictures of them "as if they wanted to be on TV or something".
He said they were running up and down the road, urging people to take pictures. "In my opinion, they were waiting for the police to arrive to be shot by the police. That's the only thing I can think," he said.
Witnesses also took to Twitter to describe the dramatic events and post photographs, which quickly spread online and on television news programmes. One user, writing on the account @Boyadee, said he saw two men decapitate another man in front of him as he went to a nearby shop. He suggested that the men looked like they were on drugs, waiting for the police to arrive and then going towards them with "just two machete and an old rusty lookin revolver".