One gunman has been killed and two more may be at large after a shooting left multiple victims dead early Monday at a U.S. Naval base in Washington, D.C.
The city's police chief said officers are looking for two other men, but could not confirm there are more shooters.
She also could not confirm the number of dead. News reports quote unnamed military officials as saying there may be as many as six fatalities at the Navy headquarters. At least four other people were wounded.
Security officers continue searching the facility.
At the White House, President Barack Obama said he is mourning "yet another mass shooting'' and called it a "cowardly act.'' He said the victims and their families need America's love and support.
The Washington Navy Yard is located about two kilometers from the U.S. Capitol.
The shooting took place at the Naval Sea Systems Command headquarters where about 3,000 people work. The Command is in charge of engineering, building, buying and maintaining ships, submarines and combat systems.