Mark Rowley, Britain's most senior counter-terrorism officer, told reporters the attack started when a car was driven over Westminster Bridge, hitting and injuring members of the public and three police officers. "A car then crashed near to parliament and at least one man, armed with a knife, continued the attack and tried to enter parliament," Rowley said. He said the police's "fast-paced investigation" was working on the assumption that the attack was "Islamist-related terrorism". Police believed they knew the identity of the attacker but would not provide details at this stage, he said. It was the deadliest attack in London since four British Islamists killed 52 commuters and themselves in suicide bombings on the city's transport system in July 2005, in London's worst peacetime attack. It took place on the first anniversary of attacks by Islamist militants that killed 32 people in Brussels. Reuters reporters inside parliament during Wednesday's attack heard loud bangs and shortly afterwards saw the knifeman and the stabbed policeman lying on the ground in a courtyard within the gates of parliament. The dead police officer was identified as Keith Palmer, 48, with 15 years of service.Five people including a police officer killed in UK terror attack.
Latest: https://t.co/5NEbd4qj7o pic.twitter.com/Bm1Y3Q7cd4— BBC News (UK) (@BBCNews) March 22, 2017
Lawmakers caught up in chaos
A Reuters photographer saw at least a dozen people injured on the bridge. His photographs showed people lying on the ground, some of them bleeding heavily and one under a bus. A woman was pulled alive, but with serious injuries, from the Thames, the Port of London Authority said. The circumstances of her fall into the river were unknown. Three French schoolchildren aged 15 or 16 were among those injured in the attack, French officials said."No signs of life"
Eyewitnesses described scenes of panic during the attack. "I just saw a car go out of control and just go into pedestrians on the bridge," said Bernadette Kerrigan, who had been on a tour bus on the bridge, in an interview with Sky News. "As we were going across the bridge, we saw people lying on the floor, they were obviously injured. I saw about 10 people maybe. And then the emergency services started to arrive. Everyone was just running everywhere." Former Polish Foreign Minister Radoslaw Sikorski, who witnessed the attack from a taxi as he crossed the bridge, said he saw five victims and made a video of the scene. "I heard something that sounded like a small car crash. Then I looked out of the window and saw that there was one person lying on the asphalt," he told Reuters. "I did not see the face of the person lying on the asphalt, but the person was not moving, it was not showing any signs of life. One of the men I saw, his head was bleeding very badly. But the person I filmed -- no, that person was not showing any signs of life." Journalist Quentin Letts of the Daily Mail newspaper told LBC radio that he had witnessed the stabbing of the policeman and the shooting of the assailant from his office in the parliament building."He (the assailant) ran in through the open gates ... He set about one of the policemen with what looked like a stick," Letts said. "The policeman fell over on the ground and it was quite horrible to watch and then having done that, he disengaged and ran toward the House of Commons entrance used by MPs and got about 20 yards or so when two plain-clothed guys with guns shot him."After shots are fired outside Parliament https://t.co/sasfLMQb5y here's the latest video from the scene in London: pic.twitter.com/tC5zzPn2CW— Bloomberg (@business) March 22, 2017