WASHINGTON — In an act of violence that sent shock waves through the American military establishment and raised questions about base security, an Army psychiatrist armed with two handguns opened fire Thursday afternoon on the grounds of Fort Hood, the country's largest military base. Twelve people, were killed and at least 31 others injured. The base, home to about 70,000 soldiers and their families, was locked down.
Army officials identified the attacker as Nidal Malik Hasan, 39, a major who recently had been promoted from captain and worked at the Darnell Army Medical Center, Fort Hood's hospital.
Authorities said immediately after Thursday's attack that they had killed Hasan. But a spokesman later said the suspected shooter was alive and in stable condition after being shot at least four times.
Officials with access to the psychiatrist's records told the Associated Press that Hasan, who was single and had no children, had worked at Walter Reed Army Medical Center in Washington for six years before being transferred to the Texas base in July. They said he received a poor performance evaluation while at Walter Reed.
Two other soldiers taken into custody following the deadly rampage were released, Fort Hood spokesman Christopher Haug said. "They're not believed to be involved in the incident."
President Barack Obama lamented the attack as a "horrific outburst of violence" and promised justice. "We are going to stay on this," he said.
"These are men and women who have made the selfless decision" to protect the nation, Obama said of the victims. "It is horrifying that they should come under fire at an Army base on American soil."
Shooting broke out about 1:30 p.m. central time at a personnel and medical processing office, said Lt. Col. Nathan Banks, an Army spokesman.
The base was locked down after the shootings, and people who live there were told to lock their doors and windows.
Families, used to being separated during long deployments, were separated again in a situation that, to many, seemed surreal.
"My friend's husband called her from Iraq and said, 'Isn't it sad that I am safer over here in Iraq than you are at home?' " said Jessica Sullens, 28, who had spent hours in a nearby Wal-Mart parking lot, where she had dashed on an errand. Her husband, Cpl. Thomas Sullens, and their 1- and 2-year old daughters were in lockdown on the base — he with his motor pool, the children with a neighbor. "This is unreal to me," Sullens said.
Around the country, some military bases stepped up security precautions, but no others were locked down. Air Force officials at MacDill Air Force Base, which has security in place at all times, would not discuss specifics about protection measures on Thursday.
"Our condolences go out to the victims' families and friends of the Fort Hood shooting," said Col. Larry Martin, 6th Air Mobility Wing commander at MacDill.
Army officials said they do not know whether the handguns used in the assault were military-issued service weapons or personal weapons.
The rules for carrying weapons on an Army post are standard throughout all bases, service officials said. The only personnel allowed to openly display weapons on the base are military police. Service weapons are checked daily and are usually only allowed to be removed from an arms room for training on a range or maintenance. Personal weapons must be kept locked and registered with the base provost marshal. The military police keep a record of all of the weapons on a base, Army officials said.
Monica Cain brushed back tears as she explained she was unable to reach her husband, whom she had taken to Fort Hood earlier in the day for medical treatment of a head injury he suffered in combat. Sgt. Barren Cain had told her he planned to call at 1 p.m. to summon her to pick him up. But by mid afternoon, after news of the shooting spread across the region, she hadn't heard from him and was unable to reach him.
"I don't know what's going on," she said. "I'm very scared."
The wounded were dispersed among hospitals in central Texas.
Lisa Pfund of Random Lake, Wis., says her daughter, Amber Bahr, 19, was shot in the stomach but was in stable condition. "We know nothing, just that she was shot in the belly," Pfund said.
Fort Hood, which sprawls across 339 square miles of central Texas hill country, is the world's largest military installation. It supports two full armored divisions — the 1st Cavalry Division and the 4th Infantry Division — and is home to more than 70,000 soldiers, civilian workers and family members. It is the largest single employer in Texas.
Base personnel have accounted for more suicides than any other Army post since the U.S. invasion of Iraq in 2003, with 75 tallied through this July. This year, 117 active-duty Army soldiers were reported to have committed suicide, with 81 of those cases confirmed — up from 103 suicides during the same period last year. Ten suicides have been reported at Fort Hood this year.
Three of the four brigades of the 1st Calvary Division are in Iraq. The three brigades — the first, second and third — are on their third Iraq tour. The division's newest brigade, the fourth, has done two tours in Iraq, returning most recently in June.
Fort Hood also is home to three of the brigades of the 4th Infantry Division. The fourth brigade is now in Afghanistan. The first brigade has done three tours in Iraq, returning most recently in March. The second brigade has also done three tours, returning most recently in September.
The military has not released the names of those who were wounded or killed.
Information from the Associated Press, New York Times and Los Angeles Times was used in this report.