The U.S. Capitol was put on a security lockdown Thursday afternoon after gunshots were reported fired outside the building.
U.S. Capitol police report at least one person wounded in the shooting. The victim has been identified as a Capitol police officer.
The reports come during a partial government shutdown that began Monday after congressional lawmakers could not reach agreement on a spending bill.
In a notice sent by email, Capitol police advised people inside all House of Representatives office buildings to "close, lock and stay away from external doors and windows."
VOA congressional correspondent Cindy Saine said some members of Congress were locked inside the House chamber.
The Senate halted all business for a time, and the Secret Service said it has cleared people off Pennsylvania Avenue in front of the White House "out of an abundance of caution."