Police shot dead a suspected gunman, but said they were looking for two other possible gunmen wearing military-style uniforms following the incident, which started about 8:30am local time (2:30pm British time).
Authorities identified the dead gunman as a US Navy employee whose work status had been changed earlier this year. While that may suggest the
motive was job-related, authorities have not ruled out anything, including terrorism.
Of the people injured, one was a District of Columbia police officer and two were female
Janis Orlowski, chief operating officer of Washington Hospital Centre, said the police
officer had gunshot wounds to the legs. One woman had a gunshot wound to the shoulder, and the other had gunshot wounds to the head and hand.
Witnesses at the heavily guarded site, which has several thousand military and civilian workers, yesterday described a gunman firing down on a cafeteria from an upper floor and a gunman firing at people in a hallway on another floor.
President Barack Obama said he is mourning “yet another mass shooting” and called it a “cowardly act.” The shooting led to tightened security at the Capitol nearby.
Eyewitness Todd Brundidge said he and other colleagues encountered a gunman in a hall on the third floor. The gunman was wearing all blue, he said.
“He just turned and started firing,” Mr Brundidge said.
Terrie Durham said she also saw the gunman. “He aimed high and missed,” she said. “He said nothing.
“As soon as I realised he was shooting, we just said ‘Get out of the building’.”
Rick Mason said a gunman was shooting from a fourth-floor balcony in the hall outside his office. He said the gunman was aiming down at people in the building’s cafeteria. Mr Mason said he could hear the shots but could not see a gunman.
Shortly after the gunfire, Mr Mason said someone on a public address system told workers to seek shelter and later to head for the gates at the complex.
Patricia Ward was in the cafeteria. “It was three gunshots straight in a row – pop, pop, pop. Three seconds later, it was pop, pop, pop, pop, pop, so it was like about a total of seven gunshots, and we just started running,” Ms Ward told reporters.
She said security officers started directing people out of the building with guns drawn.
The attack unfolded only a short distance from the White House and the US Capitol at a former shipyard that is one of the navy’s oldest shore facilities.
About 3,000 people work at the Naval Sea Systems Command headquarters, which builds, buys and maintains the US Navy’s ships and submarines and combat systems.
The facility is a favourite for official military ceremonies. The Chief of Naval Operations, Admiral Jonathan Greenert, formally welcomed his Chinese counterpart to the United States in a ceremony there last Thursday.
The shooting hit the military establishment less than three weeks after US Army psychiatrist Major Nidal Hasan was sentenced to death for murdering 13 people in 2009 at Fort Hood, Texas, where he gunned down unarmed soldiers in what he later called retaliation for US wars in Muslim countries
Pentagon spokesman George Little said defence secretary Chuck Hagel was receiving regular updates on the situation and was “obviously very concerned of reports that there has been loss of life”. Mr Little declined to provide additional details on the situation, saying it remained “fluid and ongoing”.