Washington, Nov 6 (DPA) At least one gunman opened fire on a US Army base in Texas Thursday, killing 11 people before being shot and killed by police, authorities said.

An additional 31 people were wounded in the incident at Fort Hood and were being treated in nearby hospitals, Lieutenant General Robert Cone, the base commander, said. The dead gunman was a soldier and was armed with two handguns, he said.

“It’s a terrible tragedy. It’s stunning,” Cone said.

Two other soldiers were in custody and being questioned for possible involvement in the shootings, he said. There were eyewitness accounts of a second or third shooter, he added.

Cone could not say what the motive was behind the attack that took place in a readiness centre, where soldiers are processed and medically examined before deploying to battle.

“We don’t know that right now,” he said. “This is all under investigation.”

One of the deceased victims was a civilian police officer on the base, Cone said.

The base, the largest US military installation in the world, was immediately placed on lockdown and traffic into and out of the base was closed, Cone said. A message on the Fort Hood website said: “Effective immediately Fort Hood is closed” and ordered all commanders to account for personnel.

Fort Hood, which lies about 95 km north of Texas’s capital city Austin, houses several units that have been deployed to the wars in Iraq and Afghanistan.

More than 40,000 soldiers and their families live on the base.

US President Barack Obama broke from his planned remarks at a Native American conference in Washington, calling the attack “tragic” and a “a horrific outburst of violence.”

“It’s difficult enough when we lose these brave Americans in battles overseas,” he said. “It is horrifying that they should come under fire on an Army base in the United States.”