A man has been arrested on suspicion of terror offences after three people were injured when a car crashed into security barriers outside the British parliament in London.
The silver Ford Fiesta hit cyclists and pedestrians at 7.37am before crashing into the security barriers.
Sources say the suspect is a man in his 20s from the UK.
Three people were treated at the scene, two of whom were taken to hospital.
A woman has serious but not life-threatening injuries while a man has been discharged.
The incident is being investigated by counter-terror officers.
The driver, wearing a white shirt and a black hooded puffer jacket, was detained at the scene.
The man was led backwards away from the car after police held him at the scene for a few moments.
Image: Sam Lister/PA Wire/PA Images
The Metropolitan Police said: "There was nobody else in the vehicle, which remains at the scene and is being searched. No weapons have been recovered at this stage."
In a statement, Assistant Commissioner Neil Basu said: "There is no intelligence at this time of further danger to Londoners or to the rest of the UK connected to this incident.
"Our priority is to formally establish the identity of the suspect and his motivation if we can. He is not currently co-operating."
He said detectives are making "urgent" enquiries to ensure the safety of the public, but the suspect does not appear to be known to either MI5 or British counter-terror police.
A number of armed officers appear to have been stood down, and forensics officers have arrived to begin investigations.
A later update added: "While we are keeping an open mind, the Met's counter-terrorism command is leading the investigation into the #Westminster incident."
We are now in the process of removing our wider cordons, thanks for your patience and understanding. The immediate scene, Abingdon Street, between Parliament Square and Horseferry Road, j/w Lambeth Bridge, will remain cordoned off for some time.
— Metropolitan Police (@metpoliceuk) August 14, 2018
Police there have appealed for information from anyone nearby at the time of the incident.
Video footage shows the car driving next to the Parliament Square, before turning toward Westminster Abbey.
An ambulance passes the car on its right-hand side, and the car swerves left, crossing oncoming traffic and the pavement, before crashing into the barrier.
A police officer jumps out of the way as the crash happens.
British Transport Police said they would have more officers on patrol after the incident.
Witness Ewalina Ochab said: "I think it looked intentional - the car drove at speed and towards the barriers."
She added: "I was walking on the other side [of the road]. I heard some noise and someone screamed. I turned around and I saw a silver car driving very fast close to the railings, maybe even on the pavement."
The suspect did not get out of the car, she added.
According to witnesses, cyclists were seen "lying in the road" after the crash.
Westminster Underground station was closed for a period of time, while streets around Parliament Square, Millbank and Victoria Tower Gardens were cordoned off but have re-opened.
UPDATE: Parliament Square has now re-opened following an earlier emergency services incident. St Margaret Street remains closed for the time being. Traffic flows have mostly returned to normal for the time of day. There are some residual delays on York Road.
— TfL Traffic News (@TfLTrafficNews) August 14, 2018
The Westminster parliament is in summer recess, and so there are fewer politicians working in London.
However there are numerous other people working nearby, including political journalists.
MI5's headquarters is also nearby.
