An Army psychiatrist opened fire with two handguns at the Fort Hood Army post on Thursday, killing 12 and wounding 31 others, Army officials said, adding the suspect had not been killed as previously believed.

A US Army officer identified as Major Malik Nadal al-Hasan opened fire on a base in Texas Thursday, killing 11 people before being shot to death by the police. FOX News reported al-Hasan was about to deploy to Iraq or Afghanistan. He was believed to be 39 or 40 years old, CNN said. The Army also apprehended two other soldiers suspected in what appears to be the worst mass shooting at a U.S. military base.

Authorities identified the suspected gunman as Major Nidal Malik Hasan, who had treated soldiers wounded in foreign wars preparing for foreign deployment at the post.

"Our investigation is ongoing but preliminary reports indicate that there was a single shooter," Lieutenant-General Robert Cone, Fort Hood's commanding officer, told a news conference. "The shooter is not dead but in custody in stable condition."

Cone said the suspect had been shot multiple times. He previously said the suspect was killed by police officers during the attack at the biggest military facility in the world.

A swat team enters the main gate at Fort Hood, Texas, Thursday, Nov. 5, 2009.

Can't rule out terrorist act

Asked whether the shootings were a terrorist act, Cone said, "I couldn't rule that out, but I'm telling you that right now the evidence does not suggest that."

The Army said the gunman opened fire at about 1:30 p.m. CST (1930 GMT) at the Soldiers Readiness Processing Center, a group of buildings where soldiers were getting medical check-ups before leaving for overseas deployments.

Cone said the gunman had two weapons, one of them a semi-automatic. "There is no indication that they were military weapons," he said.