The gunman, first said to have been killed, was wounded but alive and in stable condition under military guard, said Lt. Gen. Bob Cone, the base commander at Fort Hood. "I would say his death is not imminent," Cone said. Col. Ben Danner said the suspect was shot at least four times.

The suspect was identified as Maj. Nidal Malik Hasan, 39, an eight-year veteran from Virginia. The Washington Post reported that he was shot by a civilian police officer. A fellow police officer was reported killed.

President Obama called the shooting at the Soldier Readiness Center, where soldiers who are about to be deployed or who are returning undergo medical screening, "a horrific outburst of violence."

"It's difficult enough when we lose these brave Americans in battles overseas," the commander in chief said. "It is horrifying that they should come under fire at an Army base on American soil."

There was no official word on motive. Hasan had transferred to Fort Hood in July from Walter Reed Medical Center, where he received a poor performance evaluation, according to an official who spoke on condition of anonymity.

Sen. Kay Bailey Hutchison (R., Texas) said generals at Fort Hood told her that Hasan was about to deploy overseas. Retired Col. Terry Lee, who said he had worked with Hasan, told Fox News he was being sent to Afghanistan.

Video from the scene showed police patrolling the area with handguns and rifles, ducking behind buildings for cover. Sirens could be heard wailing while a woman's voice on a public-address system urged people to take cover.

"I was confused and just shocked," said Spec. Jerry Richard, 27, who works at the center but was not on duty during the shooting. "Overseas you are ready for it. But here you can't even defend yourself."

Soldiers at Fort Hood do not carry weapons unless they are doing training exercises.

The shootings sent a shudder through America's military that was felt in New Jersey, where a group of six radical Islamist men were convicted last year of planning to attack U.S. soldiers at Fort Dix in Burlington County in 2007.

"With the recent activities at Fort Hood, Texas, Joint Base McGuire-Dix-Lakehurst has increased our security measures," Angel Lopez, director of base public affairs, said in a statement yesterday. "The installation is not closed."

The base has various levels of security, Lopez said, but declined to say how the Fort Hood attack affected the measures taken by soldiers and police there.

"We do not release specific details about the security processes we have in place," she said. "As always, our goal is to ensure Joint Base McGuire-Dix-Lakehurst remains safe and secure for both personnel and the local community."

In an interview later, Lopez said she "can't speak for what people [on the base] are talking about right now.

"But you can be pretty sure it's [the shootings at Fort Hood] the number-one topic because it's all over news," she said. "We do have security measures in place. These are security measures we have every day."

Around the country, other bases stepped up security precautions, but none was locked down.

Fort Hood is the home base for more than 50,000 soldiers, and has absorbed more fatalities in Iraq and Afghanistan than any other base. The assault targeted a ceremony inside an auditorium of the Soldier Readiness Center, which provides medical and dental care to troops before they mobilize for overseas duty.

The readiness facility holds hundreds of people and is one of the most populated parts of the base, said Steve Moore, a spokesman for III Corps at Fort Hood.

Officials said the gunman opened fire on waiting areas as soldiers from across the base waited for appointments.

The Rev. Greg Schannep was about to head into the graduation ceremony when a man in uniform approached him, warning him that someone had opened fire. Schannep heard three volleys of gunfire and saw people running.

"There was a burst of shots and more bursts of shots and people running everywhere," said Schannep, who works for Rep. John Carter (R., Texas), the local congressman.

The uniformed man who had warned him ran to the theater. Schannep said he could see the man's back was bloodied from a wound. The man survived, was treated, and will recover, Schannep said.

Cone said initially that three people were held, and all had been interviewed. Authorities believe, however, that there was a single shooter.

The wounded were dispersed among hospitals in central Texas, Cone said.

Hasan is single with no children. He graduated from Virginia Tech, where he was a member of the ROTC and earned a bachelor's degree in biochemistry in 1997. He received his medical degree from the military's Uniformed Services University of the Health Sciences in Bethesda, Md., in 2001.

The attack happened just down the road from one of the worst mass shootings in U.S. history. On Oct. 16, 1991, George Hennard smashed his pickup truck through a Luby's Cafeteria window in Killeen and fired on the lunchtime crowd with a high-powered pistol, killing 22 people and wounding at least 20.

Covering 339 square miles, Fort Hood is the largest active-duty armored post in the United States. The base officially opened Sept. 18, 1942, and was named in honor of Confederate Gen. John Bell Hood.

Washington Post.