It's not clear how or why two men attacked a man believed to be a British soldier in the London neighborhood of Woolwich, but U.K. officials are already investigating it as a possible act of terrorism.

A video broadcast by the U.K. network ITV purports to show one of the two attackers explaining himself to a camera immediately after the attack. His hands are covered in blood, a knife and a machete in his right hand. The victim is clearly visible on the ground with a crowd gathering in the background. Here's what he said:

We swear by Almighty Allah we will never stop fighting you. The only reasons we have done this is because Muslims are dying every day. This British soldier is an eye for an eye a tooth for tooth. We apologise that women had to see this today but in our lands our women have to see the same. You people will never be safe. Remove your government. They don't care about you.

The Guardian cites eyewitnesses as describing the attack as a "beheading." The BBC talked to an eyewitness who describes what he saw after arriving in the middle of the attack:

I saw two people lying over him and I thought they were trying to resuscitate him. I went down to the garage and another bloke come along and told me they were actually stabbing him. Apparently they actually ran the car into him and knocked him down before they did anything. And the next minute a silver car came along and a man got out and shouted he was going to phone the police. The next thing that happened was he actually pulled a handgun out. It was a gun that looked as if it could take about 12, 15 rounds so I definitely know it was handgun because I actually seen it in his hand.

The same witness also said that some unarmed police were nearby but did not want to approach the men, who appeared to be armed, until armed "Trojan" police arrived.

The two attackers were shot by police and are currently receiving medical treatment.

Update: The Washington Post's Anthony Faiola, reporting from London, listened to the ITV video very carefully and came away with a different quote than the one circulating in British media. The first part of the attacker's quote is difficult to hear because the ITV anchor is speaking over him. It's not clear to me where the above version, which is cited in The Guardian and elsewhere, first appeared. Here's the quote as heard by Faiola: