Update at 12:26 p.m. ET: Jerry Nelson told the Des Moines Register that his daughter, Staff Sgt. Joy Clark, 27, was among the wounded. "Someone in front of her was shot and fell and was bleeding," he said. "She attempted to protect him, and that's when she was shot."

Update at 9:22 a.m. ET: Private 1st Class Michael Pearson, 21, of Bolingbrook, Ill., who joined the Army last year, was the 13th killed, his mother, Sheryll Pearson, tells the Chicago Tribune.

She says he joined the Army because he had been working at a furniture company and "felt he was in a rut. He wanted to travel, see the world. He also wanted an opportunity to serve the country."

Army Reserve Spc. Keara Bono was among the 30 people injured at Fort Hood, her family tells the Kansas City Star.

Her mother, Peggy McCarty, says Bono, 21, was preparing to go to Iraq.

"I didn't know I had to worry about her getting shot down in Texas," McCarty tells the newspaper as she prepared to fly to Texas.

Bono's brother, Dustin Bono, says his sister told him, "They shot me! And I'm still here in this country," the newspaper reports.

Update at 7:44 a.m. ET: Col. John Rossi tells reporters that the initial shooting lasted about 10 minutes and the entire incident played out over about 30 minutes before the suspect was shot and subdued by police who responded to the scene.

Update at 7:35 a.m. ET: At Fort Hood, hospital commander Col. Steven Braverman says at a morning news conference that about half of those hospitalized required surgery and that all are in stable condition.

Update at 7:17 a.m. ET: The FBI, local police and other agencies searched Hasan's apartment Thursday night after evacuating the complex in Killeen, said city spokeswoman Hilary Shine, according to the AP.

Update at 7:14 a.m. ET: One more death from the shooting was announced early Friday by Fort Hood Spokesman Tyler Broadway, bringing the death toll to 13.

Update at 9:45 p.m. ET: The military psychiatrist suspected of being the shooter is not dead, after all. From USATODAY.com's story:

The suspect in a mass shooting Thursday at Fort Hood in Texas is alive, the military said Thursday. Maj. Nidal Malik Hasan has been identified as the shooting suspect in the the attack that left 12 dead and 31 wounded at the Army base, Lt. Gen. Robert Cone, commanding general III Corps and Fort Hood, said in a press conference Thursday night. The military in an initial press conference had indicated the suspect was dead. Cone did not offer explanation for the mistake, other than to say there was confusion at the hospital. ... Cone said Thursday night that Hasan was in stable condition but not speaking to investigators. When asked further about Hasan's condition, Cone replied, "I would say his death is not imminent."

Update at 8:12 p.m. ET: FOX News interviewed Col. Terry Lee, who worked with Hasan. Here are some excerpts Fox provided:

"He said, 'Maybe the Muslims should stand up and fight against the aggressor." At first we thought he was talking about how Muslims should stand up and help the armed forces in Iraq and in Afghanistan, but apparently that wasn't the case." "He would make comments to other individuals about how we should not be in the war in the first place … He made those comments and he stuck strongly to his faith, but, as soldiers we have a duty to follow orders from our commander in chief and our political views are set aside." "He was hoping that President Obama would pull troops out. ... When things weren't going that way he became more agitated, more frustrated with the conflicts over there. ... He made his views well known about how he felt about the U.S. involvement in Iraq and Afghanistan."

Update at 7:30 p.m. ET: The death toll has risen to 13, KCEN-TV is reporting. The victim died in a local hospital.

Meanwhile, the Associated Press is correcting the gunman's name to Nidal Malik Hasan. AP also says that two soldiers who were detained have been released.

Update at 7:13 p.m. ET: AP reports that Hasan received a poor performance evaluation for his work at Walter Reed, where he worked for six years before being transferred to Fort Hood in July, according to officials who spoke anonymously. He was born in Virginia, was single and had no children.

Hasan graduated from Virginia Tech University in 1997, and in 2001 received his medical degree from the military's Uniformed Services University of the Health Sciences, in Bethesda, Md. He did his internship, residency and fellowship at Walter Reed.

Update at 7:08 p.m. ET: CNN reports that Hasan was 39, licensed in Virginia and had worked at Walter Reed Army Medical Center before practicing at Darnall Army Medical Center at Fort Hood.

Besides Hasan, the dead include 10 soldiers and a civilian police officer working on the base as a contractor.

Update at 6:57 p.m. ET: Fort Hood officials are asking that family members trying to reach their loved ones should send a text message instead of calling, because phone circuits are overloaded.

Also, Twitter has three main threads for sending messages or following the story: FortHood, #FortHood and #FTHood.

Update at 6:30 p.m. ET: The Waco Chapter of the American Red Cross has a website where you can check on base personnel. Register here.

Update at 6:07 p.m. ET: Maj. Malik Nadal Hasan was a psychiatrist who was on his way to Iraq and "was disturbed" about his deployment, Sen. Kay Bailey Hutchison (R-Texas) has just told PBS' NewsHour. He is believed to be in his late 30s, and AP says the Army is trying to determine whether that is his birth name or a name he adopted.

Two other soldiers in custody are suspected of being involved, but it's not clear what role they played.

Update at 5:41 p.m. ET: The Associated Press, citing a source, is identifying one of the gunmen as Maj. Malik Nadal Hasan.

ABC News reports that he was shooter who was slain.

Update at 5:30 p.m. ET: Texas Gov. Rick Perry will make a statement at 6 p.m. ET, AP says.

Update at 5:22 p.m. ET: President Obama said his thoughts and prayers are with the victims and families of the Fort Hood shootings and that his administration is working with law enforcement to get the details of what happened, USA TODAY White House correspondent David Jackson reports.

Saluting the sacrifices of the fallen, Obama said: "It is horrifying that they would come under fire at a military base on American soil."

He called it "a horrific outburst of violence."

Obama made his comments before making final remarks at the White House Tribal Nations Conference. He shortened his speech because of the shootings in order to return to the White House.

Update at 5:11 p.m. ET: USA TODAY's Donna Leinwand spoke with the wife of a soldier. Here's her report:

Sirens wailed at Fort Hood as Tammy Biggers, wife of an Army specialist deployed in Iraq, huddled in her locked house, texting her daughter at the local high school and fielding phone calls from family and friends.

"It's just nerve wracking. They are just now reporting that there's a possibility that there's a another shooter shooting at residences," Biggers said in a telephone interview with USA TODAY. "They just did the overhead warnings again for everyone to seek shelter immediately. It's going off right now."

The basewide siren and announcement system, usually used to warn of tornadoes, instructed base residents to seek shelter, lock their doors and turn off the air conditioning, Biggers says.

Biggers had been outside her house with their chihuahua when she heard the first sirens.

"Tons of sirens, way more than usual. But down here you don't think a lot about sirens. It could be a training exercise," she says. Then came the orders to seek shelter. Biggers lives in a two-bedroom on base house about a mile from where the shooting began and a half mile from the Clear Creek PX store.

She immediately called her daughter, a 10th grade student at Shoemaker High School. The school and base are in lockdown. Normal phone lines are working but cellphones are overloaded, she says.

The local news is reporting that 12 people are confirmed dead, 31 are wounded, including some SWAT members who responded to the shooting. One shooter was caught immediate. A second shooter with a high powered sniper rifle exchanged fire with the SWAT, the local news reported.

"Now I can't even get ahold of her. The cellphones are jammed. I can't even send a text," Biggers says. "They still have us on lockdown. I'm just staying right beside my computer with the news on and praying.

Update at 5:07 p.m. ET: Lt. Gen. Robert Cone said the primary shooter used two handguns.

All casualties occurred at the readiness center, where soldiers receive medical screenings before they are deployed or when they return, he added. Earlier reports said some victims were shot at a theater where graduation ceremonies were being held.

Update at 5:04 p.m. ET:

President Obama will make a statement shortly, AP reports.

Update at 5:01 p.m. ET: One gunman was killed and two others have been apprehended. All were soldiers, the Army says.

Update at 4:54 p.m. ET: The Army says the death toll has risen to 12, with 31 wounded.

President Obama said his thoughts and prayers are with the victims and families of the Fort Hood shootings and that his administration is working with law enforcement to get the details of what happened. Saluting the sacrifices of the fallen, Obama said: "It is horrifying that they would come under fire at a military base on American soil." He called it "a horrific outburst of violence." Obama made his comments before making final remarks at the White House Tribal Nations Conference. He shortened his speech because of the shootings in order to return to the White House.

Earlier reports follow:

MSNBC reports that seven people have been killed and 12 injured in a shooting at Fort Hood, Texas.

Update at 3:17 p.m. ET: MSNBC says the shooters were in military uniforms.

Update at 3:20 p.m. ET: MSNBC adds that one gunman is in custody and one is on the loose.

Update at 3:23 p.m. ET: KWTX says Fort Hood officials confirm that a "violent incident" has occurred, but offered few immediate details.

Update at 3:26 p.m. ET: FOX News reports the attack apparently happened at the Soldier Readiness Center.

It's not yet clear whether the victims are soldiers or civilians.

Update at 3:40 p.m. ET: NBC News affiliate KCEN in Waco reports that a third shooter may be involved and that the second suspect may be holed up in a building on the post.

Update at 3:49 p.m. ET: The Pentagon has confirmed seven dead and 20 wounded.

Update at 3:54 p.m. ET: The shooting occurred at about 1:30 p.m. CT (2:30 p.m. ET) at the family readiness area, Army spokesman Gary Tallman tells USA TODAY's Tom Vanden Brook. The base has been closed, he said.

A spokeswoman for the City of Killeen, where the base is located, tells USA TODAY's Donna Leinwand the Army is "asking for EMTs because it's a mass casualty event."

"They are having issues getting on and off post because they've locked it down," said spokeswoman Hilary Shine. "Right now there are a lot of questions and confusion."

Fort Hood is set up like its own city with its own fire, police and medical facility, Shine says. They have not asked for Killeen Police to assist, but the police are on call if needed, she said.

Update at 4:01 p.m. ET: USA TODAY's David Jackson has this from the White House:

White House spokesman Robert Gibbs said he has told President Obama about the shootings at Fort Hood, Texas, and that the staff is trying to get details.

"I told him what we knew," Gibbs said, adding that he is awaiting an update himself.

The president Obama did not mention the incident during remarks after meeting with President Ian Khama of Botswana. (Nor was he asked; some of the journalists had not heard about the shootings.)

Update at 4:38 p.m. ET: The Army confirms that one suspect is in custody and that at least two gunmen conducted two separate attacks — one at the readiness center, the other at a Howze Auditorium, where college graduation services were being held for soldiers who missed earlier commencements because of deployments. Soldiers, family members and representatives from eight colleges and universities were attending the ceremony.

FBI agents are traveling to Fort Hood and will work with Army Criminal Investigation Division, which is the lead agency right now, says Supervisory Special Agent Jason Pack, a spokesman for the FBI.

Update at 4:48 p.m. ET: The Austin American-Statesman interviewed Greg Schannep, an aide to U.S. Rep. John Carter, who was attending the graduation service.

He said that as he neared the entrance of a building where the service was being held, a soldier with blood on his uniform ran past him and said a man was shooting.

Schannep said the shootings appeared to have occurred in a complex near a theater where the service was scheduled. He was with the injured soldier, who he said appeared to have been struck in the shoulder but did not have life-threatening injuries.

Todd Martin, assistant for communications at the Killeen school district, said the district has seven elementary schools and two middle schools on the post itself.

"Those have been locked down since this began," Martin said. The other schools in the district outside the post have not been locked down, he said.

(Posted by Michael Winter)