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.

Read more, here.

Two people have died after a terror incident that saw a police officer stabbed and as many as a dozen people reportedly run over outside London's Parliament building on Wednesday., according to reports.

London police were called to the Parliament building at around 2:40 p.m. local time (10:40 a.m. EST) after reports of a vehicle crashing into a crowd at Westminster Bridge near Britain's parliament.

Witnesses say the alleged assailant then stabbed a police officer before he was shot down. The assailant's status is unclear.

Lidington said the Parliament complex is in lockdown. Journalists at the Parliament building said they were told to stay in their offices.

London police said on Twitter they are treating the attack as a "terrorist incident" until they know otherwise.

White House press secretary Sean Spicer said on Twitter that President Trump had been briefed on the ongoing situation.

Stay with Fox News Insider for more.

Tucker Debates Illegal Immigration With Dem Who Called ICE 'Nazis'

Sheriff Clarke: 'Subhuman Creeps' in MD Rape Case Sign of 'Failed Policies'

Peters: Tillerson Sending 'Utterly Wrong Message' by Planning to Visit Moscow

Hume: Russia Collusion Evidence Adds Up to Little Against Trump