WASHINGTON — As many as two gunmen launched an attack Monday morning inside the Washington Navy Yard, spraying gunfire on office workers in the cafeteria and in the hallways at the heavily secured military installation in the heart of the nation's capital, authorities said. At least 12 people were killed.
One gunman was dead after he fired on a police officer, and police hunted for a second possible attacker who may have been disguised in a military-style uniform, authorities said. It wasn't clear how the gunman died.
Investigators said they had not established a motive for the shooting rampage, which unfolded less than four miles from the White House. As for whether it may have been a terrorist attack, Mayor Vincent Gray said: "We don't have any reason to think that at this stage."
The FBI took charge of the investigation. The dead gunman was identified as Aaron Alexis by two federal law enforcement officials who spoke on condition of anonymity because they were not authorized to speak publicly.
One of those officials said Alexis, 34, was from Texas and is believed to have gotten into the Navy Yard by using someone else's identification card. It is not yet clear if that person was an accomplice or if the ID was stolen.
President Barack Obama mourned yet another mass shooting in the U.S. that he said took the lives of American patriots. Obama promised to make sure "whoever carried out this cowardly act is held responsible."
In addition to the dead, at least three people were wounded.
The area where the rampage took place, known as Building 197, was part of the headquarters for Naval Sea Systems Command, which buys, builds and maintains ships, submarines and combat systems. The yard is a labyrinth of buildings protected by armed guards at gates and metal detectors, and employees have to show their IDs to come and go.