9 a.m.

The Washington Navy Yard was on lockdown Thursday morning after reports of gunshots, but a senior federal law enforcement official says there has been no confirmed report of any shooting.

The official says civilian and military law enforcement officers were sweeping the Navy Yard building, which had already been largely emptied. The official was receiving detailed briefings on the situation but spoke on condition of anonymity because the person was not authorized to discuss developments with reporters.

The official also says there have been no reports of injuries.

The FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives are on the scene.

-- Associated Press writers Ted Bridis and Lolita C. Baldor contributed.