The crash outside the UK parliament that sparked a terror scare was "an accident", a friend of the suspect says.

Police arrested 29-year-old Salih Khater after he allegedly ploughed into cyclists and pedestrians in his Ford Fiesta before crashing into a security barrier.

He was held on a terrorism charge and further arrested for attempted murder, with police initially saying he was not co-operating with investigators.

But Anwar Mukhta, who said he has known Khater for eight years, told British media the current narrative will be revealed to be a "lie".

"It is an accident, it's nothing to do with terrorists, it's nothing to do with any organisation that tried to make an attack to any government department," he added.

He also described the keen footballer, a British national originally from Sudan, as a "very kind and quiet and decent person" who is "very generous" and "very smiley".

Mukhta echoed other members of Khater's community in Birmingham, saying the former accountancy student travelled to London to get a visa to see his family in Sudan.

The suspect's brother, Abdullah Khater, also told the BBC he was a "normal person" and that their family, originally from Darfur, were in a "state of shock".

Metropolitan Police counter-terrorism head Neil Basu said the force is treating it as a terrorist incident because of its apparently deliberate nature, the method used and the "iconic" location.

Footage aired on the BBC showed the car's approach towards the Parliament building, where it crossed into oncoming traffic and collided with cyclists before entering a small road and crashing into a security barrier.

Three people suffered non life-threatening injuries in what multiple witnesses described as a "deliberate" act.