In the US four people have been killed, including the gunman, and 16 others have been injured in a shooting at an army base in Texas.
A serving soldier opened fire on colleagues at Fort Hood in Texas. A lockdown was announced and was only lifted after the gunman killed himself.
The soldier, who had served in Iraq, was being treated for psychiatric problems including depression and anxiety.
Investigators are trying to establish a motive, but say there's no apparent link to terrorism.
Base commander Lieutenant General Mark Milley describes what happened:
Dr Matt Davis is from the nearby Temple hospital.
He's outlined the conditions of some of the victims they're treating:
Heartbroken
The gunman had only arrived at Fort Hood in February.
President Barack Obama said he was "heartbroken" that the base had suffered again.
It comes five years after a shooter killed 13 people at the same military base.
Asked whether security improvements made since the tragedy have been adequate, Secretary of Defence Chuck Hagel said: "Obviously when we have these kinds of tragedies on our bases, something's not working."
Army psychiatrist Major Nidal Hasan faces the death penalty for the 2009 killing spree.
In statements to the judge the American-born Muslim suggested he believed the attack was justified as a jihad against the US military campaigns in Afghanistan and Iraq.
Post traumatic stress
All those hit by the most recent killer's 45-calibre semi-automatic weapon were in the military. The gun, which had only been bought recently, had not been registered at the base.
Lt Gen Milley, the base's commanding officer said "It is believed he walked into one of the unit buildings, opened fire, got into a vehicle, fired from the vehicle, got out of the vehicle and opened fire again in another building.
"A military police officer responded. He was approaching her at about 20 feet. He put his hands up, then reached under his jacket. He pulled out his gun, she pulled out her weapon, she then engaged and he put the weapon to his head."
The soldier, who served four months in Iraq in 2011, was under review for possible post-traumatic stress disorder.
"There are reports that he self-reported a traumatic brain injury coming back from the Iraq tour," said Lt Gen Milley.
The soldier was married and had a family.
"There are some initial reports there may have been an argument in one of the unit areas."
The military base houses around 45,000 soldiers and 9,000 civilians and is the biggest in the US, covering 340 square miles.
