Possibly up to three gunmen, at least two dressed in military-style clothing, killed seven people and wounded at least five others in a shooting spree at the U.S. Navy Yard on Monday, officials reportedly said.

A suspected gunman was among the dead and Washington D.C. police said they were searching for two other possible shooters they described as one white man and one black man. Officials said not all the facts were immediately known about the shooting that began at about 8:36 a.m. EDT.