Terrorist guilty of London attack should be dealt with toughness and strength: Trump

"Another terrorist attack in London...These animals are crazy and must be dealt with through toughness and strength!," Trump tweeted.

At least three people were injured as a car crashed outside the House of Parliament here on Tuesday, the police said.

Police said one person has been arrested on suspicion of terrorist offences.

The Metropolitan Police’s Counter Terrorism Command is investigating an incident in Westminster this morning during which a number of people were injured.

"At 07:37hrs on Tuesday 14 August, a silver Ford Fiesta collided with a number of cyclists and pedestrians, before crashing into barriers outside the Houses of Parliament," the police said in a statement.

The driver of the car, a man in his late 20s, was arrested at the scene by armed officers. He was taken to a south London police station where he remains in police custody.

"He was arrested on suspicion of terrorist offences," the police said in a statement.

Reacting to the incident, London Mayor Sadiq Khan had tweeted: "A man has been arrested after a car was driven into barriers outside the Houses of Parliament. Police have confirmed that the incident is being treated as a terrorist act. All Londoners, like me, utterly condemn all acts of terrorism on our city."