Police at the US Capitol declared an "all clear" on Wednesday, after someone reported a “possible active shooter” in a call to emergency services.
"All buildings have been cleared at this time," US Capitol Police said in a post on X, the social platform formerly known as Twitter. It also said "there is no active threat at this time".
"A call came in for an active shooter. It appears to be a bad call. No injuries and no shooter were located," Washington Metropolitan Police Department spokesman Hugh Carew told reporters.
Workers inside the Senate complex were told to stay in place as the buildings were locked down.
“If you are inside the Senate Buildings, everyone inside should be sheltering in place as the report was for a possible active shooter,” the US Capitol Police said at the time of the lockdown.
Both the House of Representatives and the Senate are currently in recess.
Tyrone Marshall, who works in the Capitol complex, said security agents shouted for workers to lock their doors.
“We basically kind of stood by and we heard lots of yelling and shouting in the halls," Mr Marshall told The National.
"It was clear they that they were clearing rooms and halls, and you could hear orders from the Capitol Police that sounded very co-ordinated as they cleared rooms.”
The US Capitol was the scene of a deadly insurrection on January 6, 2021.
Mr Marshall was also working in the Capitol that day. He said Wednesday's events gave him “minor flashback".