Police work the scene on M Street, SE in Washington, where a gunman was reported at the Washington Navy Yard in Washington, on Monday, Sept. 16, 2013. (Credit: AP)
At least 12 people are dead after at shooting at a Navy shipyard this morning.
Among those shot are reportedly eight civilians, one D.C. police officer and one base security officer. That's according to CBS affiliate WUSA.
The Associated Press says one of the suspected shooters is dead; police say they are looking for two others. Police aren't saying how the deceased suspect died.
It started when the gunman reportedly opened fire at the Naval Sea Systems Command Headquarters building around 8:20 a.m. EST Monday.
Some witnesses said the shooter was on the fourth floor, aiming at people in a first floor cafeteria. Others said the gunman was on the third floor, shooting at people in a hallway. Investigators say they don't know if the witnesses are describing the same person or not.
The shooter has been described as a dark-complected black man, 5-foot-10 to 6 feet tall, weighing about 170 pounds. He was reportedly dressed in a black shirt and black hat. CBS affiliate WUSA says at one point it is believed that he barricaded himself with multiple guns.
Police do say there were two other people wearing military looking uniforms. Both were reportedly armed.
Navy Yard personnel are were told to "shelter in place." Nearby schools were put on lock-down as a precaution.
Planes at Reagan National Airport were grounded so they wouldn't get in the way of police helicopters.
About 3,000 people work at the Naval Sea Systems Command headquarters. It builds, buys and maintains the Navy's ships and submarines and its combat systems.
Keep checking here for updates.