BREAKING: 2 Shooters Down in Navy Yard Shooting, Witness Describes

9/16/13 - WASHINGTON -- Multiple people were killed and several more wounded when at least one gunman opened fire Monday at the Naval Sea Systems Command headquarters, authorities said. The Navy said "several" people were killed at the Navy Yard. Ed Buclatin, the public affairs chief for the Navy Installations Command, tweeted "four killed and eight injured." He also tweeted that reports of more than one shooter had not been confirmed.

The situation wsa very fluid. The Associated Press reported that a shooter had been "contained" in the building but was not in custody, according to a Defense Department official who spoke to AP on condition of anonymity.

WUSA-TV in Washington, citing Naval District of Washington spokesman Ed Ziegler, said four people were killed and that two shooters were "down" in the building.

A federal law enforcement official told USA TODAY that authorities have not ruled out the possibility of multiple shooters. The official who had been briefed on the matter said there were conflicting reports on the number of fatalities.