London's Metropolitan Police say that they are treating the crash outside of Parliament as a terrorist incident.
Authorities said in a statement Tuesday that a man in his 20s was arrested on suspicion of terrorist offenses after the silver Ford Fiesta collided with a number of cyclists and pedestrians before crashing into the barriers during the morning rush hour.
He is in custody. No one else was in the car, which is being searched at the scene of the accident.
Two people were hurt, but authorities said none of the injuries were life-threatening.