The United States Capitol Police, the federal law enforcement agency responsible for protecting Congress, announced they are locking down the entire U.S. Capitol Complex. They’re saying there’s a potential security threat.

UPDATE: A shooting reportedly took place in the Capitol Visitors Center. The White House is also on lockdown. The Associated Press put out a headline that a police officer was shot (fortunately not seriously, according to numerous sources) and the shooter is in custody, but no further details.

SECOND UPDATE: This from CNN …

U.S. Capitol Police shot a man Monday after he allegedly drew a gun at the Capitol Visitor Center. The man allegedly pulled out the weapon when a metal detector beeped as he tried to get into the building, and a Capitol police officer then fired at him. No officers were injured, but a female bystander was injured by shrapnel. “We believe this is an act of a single person who has frequented the Capitol grounds before,” said Capitol Police Chief Matthew Verderosa.