Map: Key Locations in Washington Shootings

At 8:20 a.m. three shots were heard coming from the Naval Sea Systems Command Headquarters at the Navy Yard in Washington, D/C.

Witnesses say shots were fired on the third and fourth floors of the building.

Mayor Vincent Gray and Washington Police Chief Cathy Lanier have confirmed that at least 12 are dead at this time.

One gunman, Aaron Alexis, 34, is dead.

Two others were being sought by police, a white man in khaki military fatigues and a black man in olive fatigues.

The white man is no longer considered a suspect.

Today’s shootings mark the largest loss of life in D.C. since 1982, when a plane crashed into the Potomac River, killing 78.

The Navy Yard employs 16,000 people, with 3,000 of working in the NSSC HQ (building 197.)