The suspect in the UK parliament crash has been named as Salih Khater by a European security source.
A man held on suspicion of deliberately targeting pedestrians outside the UK parliament is Salih Khater, a British citizen of Sudanese origin who was not previously known to intelligence agencies, a European security source says.
Police arrested a 29-year-old man after he appeared to drive his car at cyclists and pedestrians before ramming his car into barriers at Westminster.
"It is still being treated as terrorism but the motive is unknown as yet," said a European security source. Police have not given any further details about the man's identity.
Press Association reports a Facebook page for a man of the same name says he lives in Birmingham, works as a shop manager, and has studied at Sudan University of Science and Technology.
A silver Ford Fiesta used in the attack was driven from Birmingham to London late on Monday and spent almost five hours in the Tottenham Court Road area.
It was then driven around the Westminster area in central London for more than 90 minutes before it crashed into a security barrier just before 7.40am on Tuesday.
Three people were injured after the vehicle hit cyclists and pedestrians during Tuesday morning's rush hour.
Counter-terrorism officers have since conducted searches at two addresses in Birmingham and a residential property in Nottingham as part of the probe.
Police officers could be seen outside an address in Peveril Street, Nottingham, on Tuesday evening, said by neighbours to be home to six Sudanese people.
The suspect, who was said to not be co-operating with officers, was not known to security services, Metropolitan Police counter-terrorism head Neil Basu said.
He said the apparent deliberate nature of the act, the method used and the "iconic" location of parliament led the force to treat it as a terrorist incident.
Footage aired on BBC News showed the car's approach towards parliament, where it crossed into oncoming traffic and collided with cyclists before entering a small road and crashing into a security barrier.
Images posted online showed a man wearing a black puffer jacket being led away in handcuffs from the car as armed police swarmed the scene.
There was nobody else in the vehicle and no weapons were found, police said.
Basu added no other suspects have been identified and there is "no intelligence at this time of further danger" to Londoners.
The car was removed from the scene late on Tuesday night.
After a meeting of the government's emergency Cobra committee, UK Prime Minister Theresa May urged the nation to come together and carry on as normal.
In a statement May praised the "formidable courage" and professionalism of the emergency services who "ran towards" danger.
Home Secretary Sajid Javid, who also thanked the emergency services, urged people to "keep an open mind" about the incident.