A military psychiatrist, who opened fire at the U.S. Fort Hood Army base Thursday, killing 12 people and wounding another 31, was still alive, Army officials said.

Emergency personnel carry the wounded at the U.S. Army post in Fort Hood, Texas, in this video grab taken and released on November 5, 2009.[Xinhuanet/Reuters Photo]

Authorities said after the shooting spree that they had killed the suspected shooter, identified as 39-year-old military mental health doctor Nidal Malikl Hasan, but said later in the evening that he was alive and in stable condition in a hospital.

"His death is not imminent," said Lt. Gen. Bob Cone at Fort Hood, who offered little explanation for the mistake but said there was confusion at the hospital.

The shooting, believed to be the worst in history at a U.S. military base, took place at 1:30 p.m. CST (1930 GMT) Thursday at a family readiness area at Fort Hood.

Two other suspected soldiers were taken into custody following the rampage, but were released later, the office of Texas congressman John Carter said. Cater's congressional district includes the Army base.

The motive of the suspect was unclear. Reports said Hasan was going to be deployed overseas, either Iraq or Afghanistan. Before being transferred to the Texas base in July, Hasan had served at an Army medical center for six years.

Hasan "was disturbed" about his upcoming deployment, Texas Senator Kay Bailey Hutchison told a local news organization.

The Army closed the base, the largest active duty armored post in the United States with about 40,000 troops. The base was reopened Thursday evening.