Several people killed as gunman opens fire at Washington naval base
on 16/09/2013 15:59:30
The Navy said shots were fired in the building where about 3,000 people work.
People inside the building were ordered to take cover where they stood. Streets in the area were closed.
The shooter has been 'contained' but is not in custody, one official said, confirming that some of his victims had died.
Naval Sea Systems Command is the largest of the Navy's five system commands and accounts for a quarter of the Navy's entire budget.
It builds, buys and maintains the Navy's ships and submarines and their combat systems.
The Washington Post newspaper said three shooters, including at least one in military clothing, were involved.
It reported that police said at least one of the shooters was "down", but it was unclear whether that means the suspect has been arrested or shot.
Two remain at large, and police believe they have pinned down one between the third and fourth floors of one of the buildings on the site.
The White House said president Barack Obama was aware of the shootings. A spokesman said:
"The president has been briefed several times about the unfolding situation at the Washington Navy Yard by assistant to the president for Homeland Security and Counter-Terrorism Lisa Monaco and deputy chief of staff Alyssa Mastromonaco.
"The president directed his team to stay in touch with our federal partners, including the Navy and FBI, as well as the local officials. We urge citizens to listen to the authorities and follow directions from the first responders on site."