A US Army major firing two handguns has killed 13 people and wounded 30 in a shooting rampage at Fort Hood base in Texas, before being shot and captured.
The Army earlier reported that the gunman had been killed but now says he was wounded and is in a stable condition. He has been undergoing surgery.
The Army has identified him as Major Malik Nidal Hasan, 39, a psychiatrist who was due to be sent on a mission to Iraq within a month. He had treated soldiers wounded in foreign wars.
The BBC reports 11 victims were initially reported dead, but two of the injured later died, bringing the death toll to 13.
Fort Hood's commanding officer, Lieutenant-General Bob Cone, says they believe Major Hasan was acting alone.
The motive for the shooting was not known, but Major Hasan's cousin, Nader Hasan, says his cousin had been the target of harassment because of his "Middle Eastern ethnicity", even though he was born and grew up in the United States.
Began at medical centre
Lieutenant-General Cone says the shooting began about 1.30pm on Thursday at a personnel and medical centre, where soldiers who are preparing to deploy go for last-minute medical check-ups.
Fort Hood, located near the town of Killeen, is one of the largest military posts in the world. It handles tens of thousands of troops going to and from war zones in Afghanistan and Iraq.
US President Barack Obama described the shooting as "a horrific outburst of violence" and says his thoughts are with the men and women who serve at Fort Hood.
Mr Obama says the White House is working with the Pentagon, FBI and Department of Homeland Security to make sure the army base was secure.
The incident is one of the worst killings reported on a US military base.
In May a US soldier at a base in Baghdad shot dead five fellow soldiers.
It raised new questions about the toll that six years of fighting in Iraq and nearly eight years in Afghanistan have taken on the US military.