11:38 WASHINGTON (AP) - President Obama: 'We will hold those responsible for this 'cowardly act' responsible.'

11:16 WASHINGTON (AP) - DC Police Chief: May have 2 additional shooters at large after rampage at Navy Yard.

10:37 WASHINGTON (AP) - Federal Law Enforcement official says shooter at Washington Navy Yard has died.

10:34 WASHINGTON (AP) - Officials: Police looking into possibility of second shooter at Navy Yard where several killed.

10:16 WASHINGTON (AP) - Defense official: several killed, as many as 10 wounded in Navy Yard shooting and shooter is 'contained' but not in custody.

8:56 WASHINGTON (AP) — The U.S. Navy says one person is injured after a shooting at a Navy building in Washington.

Police and emergency crews gathered Monday morning outside the Naval Sea Systems Command Headquarters building, where the shooting was reported.

The Navy says three shots were fired and that that about 3,000 people work in the building. People inside the building have been directed to stay in place.

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.

Police from multiple local and federal agencies were responding along with SWAT crews.

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