Washington - Defense Official: Several Killed, Up To 10 Wounded

Washington - At least one gunman opened fire inside a building at the Washington Navy Yard on Monday morning, and officials said six people were killed and at least four were wounded, including a law enforcement officer.

Police were looking for two other potential gunmen wearing military-style uniforms, including one who had on a beret, chief Cathy Lanier said.

Authorities have identified the dead shooter as a Navy employee whose work status had been changed earlier this year, said a federal government official who spoke only on condition of anonymity because he wasn’t authorized to speak on the record. While that may suggest the motive was job related, authorities haven’t ruled out anything including terrorism, the official said. Lanier said she didn’t think the other gunmen were part of the military.

Witnesses described a gunman opening fire from the fourth floor, aiming down on people in the first-floor cafeteria. Others said a gunman fired at them in a third-floor hallway. It wasn’t clear whether the witnesses on different floors were describing the same gunman.

As emergency vehicles flooded the streets around the complex, a helicopter hovered overhead, nearby schools were on lockdown and airplanes at nearby Reagan National Airport were briefly grounded so they wouldn’t interfere with law enforcement choppers. Less than 2 miles away, security was beefed up at the U.S. Capitol and other federal buildings, but officials said there was no known threat.

President Barack Obama mourned what he called “yet another mass shooting” in the U.S. that he says took the life of American patriots. Obama promised to make sure “whoever carried out this cowardly act is held responsible.”

Two Navy officials confirmed at least six people had died. The officials spoke on condition of anonymity because they were not authorized to discuss the situation publicly.

About 3,000 people work at the Naval Sea Systems Command headquarters, which builds, buys and maintains the Navy’s ships and submarines and combat systems.

Todd Brundidge, an executive assistant with Navy Sea Systems Command, said he and other co-workers encountered a gunman in a long hallway of their building on the third floor. The gunman was wearing all blue, he said.