The US Capitol went on lockdown Friday after a vehicle rammed into a barricade outside the building. 

The driver, who appeared to have a knife, was shot by police and taken into custody. He died shortly after. 

The United States Capitol Police (USCP) tweeted Friday, "CRITICAL INCIDENT: USCP is responding to the North Barricade vehicle access point along Independence Avenue for reports someone rammed a vehicle into two USCP officers."

An initial alert from USCP warned of an 'external security threat' at the Capitol and advised everyone to remain indoors and stay away from windows.

DC Fire and the FBI Washington Field Office were also involved in responding to the incident.

The condition of the officers, who have been hospitalized, is not yet known.

A press briefing about the incident will begin shortly.