FORT HOOD, TEXAS - Army officials say four people, including the gunman, are dead, and 16 people are injured after a shooting at Fort Hood.
All of the victims were military personnel.
Officials say the shooting happened at a medical center at the base at 4 p.m. local time.
They say the shooter was a soldier who was being treated for mental health issues.
Although not diagnosed, officials say he may have had PTSD.
The soldier was not identified, but authorities say he served in Iraq in 2011 and arrived at Fort Hood in February.
Right now, there is no indication that the incident is related to terrorism.
"It is believed that he walked into one of the unit buildings, opened fire, got into a vehicle, fired from a vehicle, got out of the vehicle, walked into another building and opened fire again, and then was engaged by local law enforcement here at Fort Hood," said Lieutenant General Mark A. Milley of the U.S. Army. "The shooter is dead from a self-inflicted gunshot wound."
President Barack Obama was in Chicago for a fundraiser when he was briefed on the incident.
He promised that officials will get to the bottom of what happened.
The base was the scene of a mass shooting in 2009, when 13 people were killed and more than 30 were wounded.
It was the deadliest attack on a domestic military installation in U.S. history.
Fort Hood is about 70 miles from Austin.