PHOTOS: Fatal terror incident outside Parliament in London

At least four people are dead at after a violent incident was reported at the Westminster Bridge near the Houses of Parliament in London on Wednesday. Police also reported a "number of casualties." The suspect is believed to be among the dead.

David Lidington, the leader of the House of Commons, addressed Parliament to say that a "police officer has been stabbed" and an "alleged assailant was shot by armed police." Witnesses reported hearing gunshots.

Officials also said there were reports of a person in the River Thames as well as a car that appeared to hit bystanders on the Westminster Bridge.

Paramedics were seen treating people at the scene. Officials declared the events to be a terror incident.

This is a developing story. Check back for updates.