UPDATE: Scotland Yard said Wednesday afternoon that four people died and at least 20 were injured. The dead include the police officer who was stabbed and the attacker who was shot by an officer. Police said there was one attacker, but the investigation is continuing into the terrorist incident.
Eyewitnesses described the horrifying scene on Westminster Bridge, where an attacker ran over people before stabbing a policeman outside the U.K. Parliament.
Police said they're treating the attack as a "terrorist incident" at this juncture and at least two people were killed, with several more injured. The U.K. Parliament remains on lockdown.
The leader of the House of Commons David Liddington confirmed the suspect was shot by police.
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VIDEO: Witnesses describe the scene after a terror attack on Westminster Bridge.