The U.S. Capitol Police issued an emergency evacuation order based on an aircraft they said was a "probable threat" to the Capitol complex on Wednesday.
They later said there was no threat and that the aircraft was carrying a U.S. Army skydiving team that was parachuting into the Washington Nationals baseball stadium.
Capitol Police issued a statement at about 6:30 p.m. ordering an evacuation of the U.S. Capitol, the Capitol Visitor Center, the Library of Congress, and the U.S. Botanical Garden buildings.
Most lawmakers are out of town for a recess lasting two weeks. That recess ends next week.
The evacuation was ordered because a single engine plane was not responding to orders via radio communication and was circling Washington.
Two people told the Associated Press that the plane took off from Joint Base Andrews in Maryland and neither reported taking off nor had appropriate clearance.
The parachuting demonstration was a part of the team's celebration of military appreciation day at Nationals park, which is about a mile away from the U.S. Capitol. A few people posted videos of the sky divers and the plane on social media.
Some on Twitter mocked the authorities over the embarrassing mix-up.
"Glad that massive intelligence sharing failure we saw at Capitol Hill on Jan. 6 got fixed," tweeted journalist Ken Klippenstein.
"Somebody might be getting fired over this one," said White House correspondent Christian Datoc.
Here's more about the Capitol evacuation:
US Capitol evacuated over 'aircraft'; no threat found www.youtube.com