At least four are dead among 10 people shot, including a Washington, D.C. police officer, at the city's Navy Yard grounds.
The U.S. Navy confirmed on Twitter that there was an active shooter at the Naval Sea Systems Command Headquarters building and that at least three shots had been fired around 8:20 a.m. Approximately 3,000 people work in the building.
NBC News reported that four are dead. A Defense Department official said several people have been killed and as many as 10 have been wounded in the shooting, according to the Associated Press
The official spoke on condition of anonymity Monday because the official was not authorized to discuss the matter publicly.
The official also says the shooter is ‘‘contained’’ but not yet in custody.
Earlier in the day, the U.S. Navy said it was searching for an active shooter at the Naval Sea Systems Command headquarters, where about 3,000 people work.
A police spokesperson said the gunman had reportedly barricaded himself in a room after opening fire on at least three people.
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Authorities and D.C. Mayor Vincent Gray have ordered area residents to "shelter in place" until the shooter is subdued.
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, according to The Associated Press.
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