(AP) - A military mental health doctor facingdeployment overseas opened fire at the Fort Hood Army post onThursday, setting off on a rampage that killed 12 people and left31 wounded, Army officials said.

Authorities said immediately after the shootings that they hadkilled the suspected shooter, but later in the evening theyrecanted and said that he was alive and in stable condition at ahospital, watched by a guard.

"His death is not imminent," said Lt. Gen. Bob Cone at FortHood. He offered little explanation for the mistake, other than tosay there was confusion at the hospital.

A law enforcement official identified the shooting suspect asArmy Maj. Nidal Malik Hasan. The official spoke on condition ofanonymity because he was not authorized to discuss the casepublicly.

The violence was believed to be the worst mass shooting inhistory at a U.S. military base.

The shooting began around 1:30 p.m., when shots were fired atthe base's Soldier Readiness Center, where soldiers who are aboutto be deployed or who are returning undergo medical screening, Conesaid.

It was unclear what the motive was, though it appeared he wasupset about a scheduled deployment. U.S. Sen. Kay Bailey Hutchisonsaid the Army major was about to deploy overseas, though it wasunclear if he was headed to Iraq or Afghanistan and when he wasscheduled to leave. Hutchison said she was told about the upcomingdeployment by generals based at Fort Hood.