Eyewitnesses including tourists, reporters and MPs have spoken of their horror during what is now being treated as a terror attack in Westminster.
One woman has been confirmed dead and a number of people injured in the incident.
Commander BJ Harrington of the Metropolitan Police said there were “a number of casualties” in the Westminster attack “including police officers”, according to the Press Association.
One video from the scene showed chaos as people fled the scene:
Video also emerged of staff in the Houses of Parliament during the lockdown:
Gunfire was heard just before 3pm in central London, with a government minister confirming a police officer was stabbed and the assailant shot by armed police.
On nearby Westminster Bridge witnesses said a vehicle struck several people on the bridge, and photos showed a car ploughed into railings.
There were reports that a woman was pulled alive from the river after apparently falling from the bridge during the attack:
Eyewitnesses, many of them journalists, shared their experiences of the incident on social media...
A number of eyewitnesses gave interviews describing what they saw...
Witness Rick Longley told the Press Association that he saw a man stab a policeman outside Parliament.
“We were just walking up to the station and there was a loud bang and a guy, someone, crashed a car and took some pedestrians out,” he said.
“They were just laying there and then the whole crowd just surged around the corner by the gates just opposite Big Ben.
“A guy came past my right shoulder with a big knife and just started plunging it into the policeman.
“I have never seen anything like that. I just can’t believe what I just saw.”
MPs inside the House of Commons also shared their experiences...
Scotland Yard said the attack in Westminster was being treated “as a terrorist incident until we know otherwise”.
The Metropolitan Police added in a statement that the incident is ongoing and are urging people to stay away from the area.