Two men attacked another man near a London military barracks Wednesday, in what British authorities were investigating as a possible terror act. One man is dead and two others were injured.
While details were scant, Prime Minister David Cameron called the killing "truly shocking" and said he had asked Home Secretary Theresa May to call an urgent meeting of the government's emergency committee.
A British government official who spoke only on condition of anonymity because he was not authorized to speak about the investigation said the details that had emerged were indicative of a "terrorist-motivated attack."
May said she had been briefed by Britain's domestic security service, MI5, and by police on what she called a "sickening and barbaric" attack.
Britain's Ministry of Defense said it was urgently investigating reports that a serving soldier was involved in the incident.
Police said armed officers responded to reports of the assault Wednesday afternoon just a few blocks from a military training barracks in southeast London.
Commander Simon Letchford said reports indicated that one man was being assaulted by two other men, and that a number of weapons — including possibly a firearm — were used in the attack.
He confirmed that one man was found dead at the scene and that two men were shot by police and taken to separate London hospitals. One of them is in serious condition, according to London Ambulance Service.
Cameron's office said he was cutting short a trip to Paris to return to London, and he would chair another meeting of the emergency committee on Thursday.
Live television images of the scene showed a trail of blood staining a pavement, cordoned off streets and crime scene investigators marking the scene.
David Dixon, head teacher of a nearby primary school, said police told him there was a serious incident. He said he saw body lying in the road outside.
He told the BBC that he then made sure children were inside and put the school into lockdown mode. He said he then heard shots fired.
The Independent Police Complaints Commission, which is called in when officers are involved in shootings, confirmed that it is investigating the incident, which took place near the Royal Artillery Barracks.
The barracks — which house a number of the King's Troop Royal Horse Artillery and independent companies of the Grenadier and Coldstream Guards — were the site of shooting events during the 2012 London Olympics.