A gunman has been shot after pointing his weapon at a police officer at the US Capitol Visitor Center.
The suspect was taken to hospital after being shot by the officer at a security screen
A woman in her late 30s suffered minor injuries in the incident and was also taken to hospital.
Reports that a police officer had been wounded or that a suspect had tried to enter the White House were “incorrect”, police said.
Workers in the Capitol were told to “shelter in place” and those outside were urged to take cover.
The White House was initially put in lockdown, but this was lifted after a matter of minutes.
A police spokesman said the gunman was transported to hospital, but his condition was unknown.
It is understood the suspect was known to officers, but there did not appear to be any connection to terrorism, the spokesman said.
A weapon was recovered from the scene and the suspect’s vehicle was found on Capitol grounds, Capitol Police Chief Matthew Verderosa said.
“During routine administrative screening, the individual drew what appeared to be a weapon and pointed it at officers,” the police chief said.
He added: “Based on initial investigation, we believe this is an act of a single person who has frequented the Capitol grounds before. There is no reason to believe this is anything more than a criminal act.”
The event unfolded with Congress in recess and lawmakers back in their districts.
Armed police cordoned off the streets immediately around the Capitol building.
The streets were thick with tourists visiting for spring holidays and the Cherry Blossom Festival.
The shooting happened just a few hours after a drill for an active shooter took place at the Capitol, creating further confusion.
Cathryn Leff tweeted that she was at the visitor’s centre when she heard gunshots while going through a security check point.
“That moment when it goes down. Everyone is screaming & running and you can’t see where the #ShotsFired are from,” tweeted Leff(@Cathrynlefflmft).
Traffic was jammed in the area, but the scene was relatively calm, accordin.g to witnesses.
A work crew on the north side of the Supreme Court, across the street, was asked to stop work and move away from the building as a precaution.
The Capitol Visitor Center is where tourists gather to take tours. Mr Verderosa said it would be open as normal on Tuesday.