(CNN) -- The British government is treating the gruesome killing of a man in London's Woolwich area as a suspected terrorist attack, the British Prime Minister's office said Wednesday.
The man is believed to be a serving soldier who was based at a nearby barracks, Nick Raynsford, a member of Parliament, told CNN.
The UK government has called a meeting of its civil emergency committee, known as COBRA, to discuss the incident, the prime minster's office said.
Raynsford said the two people suspected of killing the man were taken to a hospital.
The soldier had apparently been on duty in central London and was returning to the Royal Artillery Barracks in Woolwich when he was attacked, Raynsford said.
London Mayor Boris Johnson tweeted: "This afternoon's attack in Woolwich is a sickening deluded and unforgivable act of violence. My thoughts are with the victim and his family."
It's not yet known what the motivation is for the attack.
UK Home Secretary Theresa May described it as a "a sickening and barbaric attack."
Commander Simon Letchworth told reporters in Woolwich that local officers had responded quickly when an assault was reported at 2:20 p.m. Wednesday and a firearms unit was called to the scene. British police do not usually carry firearms.
"Two men, who we believe from early reports to have been carrying weapons, were shot by police," he said. "They have both been taken to separate London hospitals and are receiving treatment for their injuries."
Eyewitnesses have given gruesome details of the killing.
One, Michael Atlee, told CNN he and friends heard gunshots and when they turned the corner saw lots of blood in the road.
The man killed appeared to be wearing a T-shirt for Help for Heroes, a charity that helps military veterans, he said.
Another witness, who gave his name only as James, told London's LBC 97.3 radio station that he saw two men standing by the victim on the floor.
At first he thought they were trying to help the man but then saw two meat cleavers, like a butcher would have.
"They were hacking at this poor guy, literally," he told the radio station, as if they were trying to remove his organs.
"These two guys were crazed. They were just not there. They were just animals."
The men appeared to want to be filmed, he said, saying that one of the attackers went over to a bus and asked people to take photos of him as if he wanted to be on TV.
He said the two men had rushed at the police when they arrived, at which point shots were fired and both men went down.
Another witness, Woolwich Theatre owner Adrian Green, said the incident was "shocking" but did not reflect the true nature of the area.
Raynsford said the military based at the centuries-old barracks had a close relationship with the local community. Woolwich is a mixed, multicultural area, he added.