DEVELOPING: At least 10 people have been shot — with multiple fatalities — at a Navy building in Washington, U.S. Navy authorities said Monday.

A Navy official said two shooters were “down” following reports of shots fired at around 8:20 a.m. at the Naval Sea Systems Command headquarters in southeast Washington. There are conflicting reports on the number of victims and the condition of the shooting suspects, although a federal law enforcement official told Fox News that one shooter has died.

Police sources earlier told The Washington Post that as many as three shooters, including one in military fatigues, were involved in the incident.

Patricia Ward, a logistics management specialist at the facility, told reporters she heard at least 7 gunshots but did not see a gunman.