All-clear at Washington Navy Yard after shooting reports

Washington

A US Navy installation in Washington was given the all-clear today after locking down for several hours over unconfirmed reports that an active gunman was on the loose, authorities said.

The Navy said on Twitter that there was "no sign of shooting" and that all personnel were fine.

Local media reported that the district police and the FBI also had given a thumbs-up after a building-to-building search of the US Navy Yard turned up no evidence of a shooter or that any shots were fired. 

The Navy Yard, a complex of naval offices in southeast Washington, was the scene of a September 2013 mass killing in which a lone gunman fatally shot 12 people before being killed himself by police.

Thursday's lockdown also came amid security jitters as the United States braces for the July 4 Independence Day holiday, with major festivities planned in the capital.

The FBI, Department of Homeland Security and National Counterterrorism Center have warned the public of an increased risk of attack during the long Independence Day weekend.

The Navy Yard was locked down at around 7:45 am (1145 GMT) on the reports of an active gunman on the premises.

Military and civilian workers streamed out of the Navy Yard, seen in television images with hands in the air, after receiving orders to evacuate or take shelter in place.