Lt. Gen. Bob Cone said Thursday evening that Maj. Nidal Malik Hasan was not killed by authorities as had been previously reported. However, the death toll remained 12 after another victim died.
Cone said the suspected shooter is alive and in stable condition.
Cone offered little explanation to reporters at a news conference as to why the suspect was believed dead, saying only there was confusion at the hospital.
"His death is not imminent," Cone said of the suspect.
Cone also updated his earlier comments that there were three suspects, saying the "evidence indicates a single shooter."
The shooting happened in a large enclosed area where Army personnel were waiting for medical and dental care, he said.
The shooter used two handguns, one of which was semiautomatic, he said. There wasn't any indication they were military-issued weapons.
Cone said there could have been more casualties, but many of the people in the room were trained in combat lifesaving techniques.
He also said that soldiers on Fort Hood do not normally carry weapons, but there are armed law enforcement officers. "This is our home," he said.
The two other soldiers taken into custody were later released, Fort Hood spokesman Christopher Haug told The Associated Press. "They're not believed to be involved in the incident," Haug said. He said a third person was in custody, however.
U.S. Sen. Kay Bailey Hutchison told the NewsHour's Jeffrey Brown that Hasan "was on his way to Iraq, and apparently was very disturbed about it."
Brown also spoke with a National Journal reporter for more:
President Barack Obama called the attacks "a horrific outburst of violence."
"It's difficult enough when we lose these brave Americans overseas," the president said. "It is horrifying that they should come under fire at an Army base on American soil."
Lt. Col. Nathan Banks, an Army spokesman in Washington, told the AP the shooting occurred at 1:30 p.m. at the base's Soldier Readiness Center where soldiers who are about to be deployed or who are returning undergo medical screening.
According to the Fort Hood Web site, the base is home to roughly 65,000 soldiers.
"This is not a Drill. It is an Emergency Situation," the base's Web site read.
In Texas, Gov. Rick Perry ordered all flags lowered to half-staff.
Fort Hood officially opened on Sept. 18, 1942, and was named in honor of Gen. John Bell Hood. It has been continuously used for armored training and is charged with maintaining readiness for combat missions. The base serves approximately 218,000 people, including service personnel, retirees, and military families.
---- Compiled from wire reports and other media sources