A man has been arrested on suspicion of terrorism offences after a car crashed outside the Houses of Parliament, injuring several people.

Officers were seen surrounding the vehicle before the man in his late 20s was detained, shortly after 07:30 BST.

London Ambulance Service said it had taken two patients to hospital with non life-threatening injuries after cyclists and pedestrians were hit.

No one else was in the car and no weapons have been found so far.

"At this stage, we are treating this as a terrorist incident and the Met's Counter Terrorism Command is now leading the investigation," said Scotland Yard.

The man is in custody at a south London police station and the vehicle is being searched. The government's Cobra emergency committee is meeting later.

A number of eyewitnesses have said the silver Ford Fiesta, which was travelling westbound, appeared to deliberately hit members of the public as it swerved into the opposite lane.

Footage released by the BBC shows the moment when the vehicle drives over a pedestrian crossing before crashing into the security barriers.

Parliament is currently not sitting.

Cyclists were seen on the ground after the crash

Westminster tube station is closed and streets around Millbank, Parliament Square and Victoria Tower Gardens have been cordoned off. Nearby Strutton Ground has also been closed to the public.

People were moved further back from the area twice as police put up a Terrorism Act cordon.

Images posted to social media showed a man in handcuffs being led away from the car by officers after the crash.

A London Ambulance Service spokesman said the two people taken to hospital had "injuries that are not believed to be serious" and a third patient with minor injuries was assessed at the scene.

BBC News home affairs correspondent June Kelly described the terror arrest as a "significant development".

"The police will be looking at this man's background, his identity - they'll either know it or they will be working towards it," she said. "They will be looking at his beliefs his associates, also his mental state.

"Also, crucially, is he on their radar - is he somebody who was known to them?"

Prime Minister Theresa May said: "My thoughts are with those injured in the incident in Westminster and my thanks to the emergency services for their immediate and courageous response."

Home Secretary Sajid Javid also thanked emergency services for their quick response.

Mayor of London Sadiq Khan said he was in close contact with police and that he "utterly condemns all acts of terrorism on our city".

Barry Williams, a BBC member of staff based at Millbank, said: "I heard lots of screams and turned round.

"The car went onto the wrong side of the road to where cyclists were waiting at lights and ploughed into them.

"Then it swerved back across the road and accelerated as fast as possible and hit the barrier at full pelt.

"It was a small silver car and he hit it at such speed the car actually lifted off the ground and bounced.

"Then the police just jumped. Two officers managed to leap over the security barriers and then the armed police vehicles all sped towards the scene."

Another witness, called Kirsty, said: "A car drove the wrong way round the road, drove through about 20 cyclists and crashed into a wall. It looks like only one woman was seriously injured."

Jason Williams told BBC Radio 4's Today programme the driver had "driven at speed - more than 40 mph".

He added: "There was smoke coming out of the car. I have seen people on the ground, lying on the road. I don't know if they have actually been hit by the vehicle or not.

"I saw at least 10 people lying down. I was told basically to move away, to run. I have run for my life."

He said that "it looked deliberate... it didn't look like an accident".

More than 10 police vehicles and at least three ambulances were at the scene outside Parliament.

Firearms officers and at least two police sniffer dogs have been searching the area.

British Transport Police said it was increasing patrols in England, Scotland and Wales and that its officers would be "highly visible on trains and at stations".

A bus driver who was driving past the scene at the time said he saw smoke coming out of the car.

Victor Ogbomo said: "I just stopped the bus. The police said we have to move back, then in less than five minutes the response team came."

Source: BBC