WASHINGTON -- The U.S. Capitol building is no longer on lockdown.

The U.S. Senate sergeant at arms said a lockdown had concluded. The sergeant at arms had earlier issued a lockdown alert for the building and visitor centre, saying police activity has been reported.

Capitol police had said they were searching for an individual but offered no details. One officer outside the Capitol said police are responding to sketchy reports of woman who may have a gun; a House Democratic leadership staffer had said the sergeant at arms office had said there had been a woman with a gun in a tunnel leading to the Rayburn House Office Building.