Last Updated 2:21 p.m. ET
President Barack Obama said Friday the entire nation is grieving for those slain at Fort Hood, and he urged people not to jump to conclusions while law enforcement officers investigate yesterday's deadly shooting at a U.S. military base in Texas.
"We don't know all the answers yet. And I would caution against jumping to conclusions until we have all the facts," Mr. Obama said in a Rose Garden statement otherwise devoted to the economy.
"What we do know is that there are families, friends and an entire nation grieving right now for the valiant men and women who came under attack yesterday," the president said.
Federal, state and local law authorities are joining in the investigation of Thursday's deadly rampage, in which a military psychiatrist facing deployment overseas allegedly opened fire, killing 13 people, before being shot by a first responder.
One of the 13 dead was a civilian.
Thirty people were also wounded, with half of those hospitalized requiring surgery, Army officials said. They are all in stable condition.
The shooting suspect was identified as Army Maj. Nidal Malik Hasan.
Lt. Gen. Robert Cone, Fort Hood's base commander, told CBS's "The Early Show" that the suspect was shot at least twice inside a building on the base, then left the building to pursue his victims as they tried to flee, firing off more rounds. Hasan was shot a total of four times during the rampage, and was initially reported to have been killed.
He is on a ventilator at a civilian hospital, under guard, and is in stable condition.
All indications are there was a single shooter, and Hasan the sole suspect, said Col. John Rossi, Deputy Commanding General - Fires and Effects at Fort Hood, although a senior U.S. official did not rule out.
Cone told "Early Show" co-anchor Harry Smith that the alleged gunman is rumored to have said "Allahu Akbar" - Arabic for "God is great!" - during the shooting, but was unable to confirm that information.
At this morning's press conference officials could not confirm that the shooter said anything during the half-hour-long incident.
Though the base is no longer under lockdown, it is operating at a heightened level of security. "We are fully confident in the security of this installation and remain so," said Rossi.
The Army is providing the post with additional grief counselors, chaplains, and public affairs support. Rossi also said this morning that about 90% of the families of victims have been notified so far.
The violence was believed to be the worst mass shooting in history at a U.S. military base. "This has been a tragic incident, and our hearts and prayers go out to all of those who have been impacted by this tragedy," said Rossi.
As of Friday afternoon, the names of four of the dead have been released:
• Spc. Jason Dean Hunt, a 22-year-old Oklahoma native, has served three and a half years in the Army, including a tour in Iraq. Hunt was married two months ago.
• Sgt. Amy Krueger, 29, from Kiel, Wis., was with the Madison-based 467th Medical Detachment. She had arrived at Fort Hood just two days before the shooting, according to her mother, Jeri Krueger, and was scheduled to be sent to Afghanistan in December.
• Pfc. Aaron Thomas Nemelka, 19, from Salt Lake City, Utah, enlisted in the Army in October 2008 and was to be deployed to Afghanistan next January as part of the 5/10th Engineering Company, 20th Infantry Battalion, 36th Engineering Brigade.
• Pfc. Michael Pearson, 21, of Bolingbrook, Ill. A neighbor in the suburb of Chicago told the Associated Press that the family has "lost their gem."
White House spokesman Robert Gibbs said today a memorial service will be scheduled at the convenience of families who lost loved ones, and that President Obama would attend.
Military officials say they are still piecing together what may have pushed Hasan, an Army psychiatrist trained to help soldiers in distress, to turn on his comrades.
and are looking for clues that may have led to the military massacre.
Cone says Hasan was not known to be a threat or risk, and that military officials will interrogate him as soon as possible.
The shooting began around 1:30 p.m., when shots were fired at the base's Soldier Readiness Center, where soldiers who are about to be deployed or who are returning undergo medical screening.
More Coverage of the Tragedy at Fort Hood:
Hasan Likely "Lone Wolf," Officials Say
Hasan Reportedly Felt U.S. Attacked Islam
List of Fort Hood Dead, Wounded
Neighbor: Ft. Hood Suspect Packed Up Home
"Allahu Akbar": Hasan's Words as He Fired?
Mosques Up Security in Wake of Ft. Hood
Obama: Don't Jump to Conclusions
Hasan's Actions "Despicable," Family Says
Female Cop Hailed as Ft. Hood Hero
Store's Video May Show Ft. Hood Suspect
U.S. Army Base Violence Has Bloody History
Tragedy at Fort Hood
Fort Hood spokesman Christopher Haug said Friday that the guns used in the attack were believed to be Hasan's "own private firearms."
It was, though it appeared he was upset about a scheduled deployment. U.S. Sen. Kay Bailey Hutchison said the Army major was about to deploy overseas, though it was unclear if he was headed to Iraq or Afghanistan and when he was scheduled to leave. Hutchison said she was told about the upcoming deployment by generals based at Fort Hood.
The victims of the shooting have not been identified but Cone said Thursday night that the slain included U.S. soldiers and a civilian police officer working at the base. He said that no children had been killed to his knowledge.
"It's a terrible tragedy. It's stunning," Cone said. "Soldiers and family members and many of the great civilians that work here are absolutely devastated."
The wounded are dispersed among several central Texas hospitals and the extent of their injuries varied, Cone said.
Statement From Suspect's Family
Hasan, 39, is a licensed psychiatrist who has lived in Bethesda and Silver Spring, Md. and various places in Virginia, where he grew up. A spokesman for Texas Sen. Hutchison said Hasan was upset about an upcoming deployment to Iraq.
He is an American citizen of Jordanian descent, and a lifelong Muslim.
He is a graduate of Virginia Tech University, 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.
Military officials say Hasan worked at the Walter Reed Army Medical Center in Washington, D.C. (where he did his internship, residency and a fellowship) for six years before being transferred to the Texas base in July. The officials had access to Hasan's military record. They said he received a poor performance evaluation while at Walter Reed.
In a statement released to the media Thursday night, Hasan's family said they were "shocked and saddened by the terrible events at Fort Hood."
The full statement from the unnamed cousin said: "Nidal was an American citizen. He was born in Arlington, Virginia and raised here in America. He attended local high schools and eventually went on to attend Virginia Tech. We are filled with grief for the families of today's victims. Our family loves America. We are proud of our country, and saddened by today's tragedy. Because this situation is still unfolding, we have nothing else that we are able to share with you at this time."
Faizul Khan, a former imam at a mosque Hasan attended in Silver Spring, Maryland, said he spoke often with Hasan about how Hasan wanted to find a wife. Hasan was a lifelong Muslim and attended prayers regularly, often in his Army uniform, Khan said.
Video from a convenience store thatmaking a purchase just hours before the alleged attack shows him wearing a shalwar kameez, a traditional robe worn primarily in Afhganistan and Pakistan - but not in the Arab world where Hasan has his roots.
CBS News correspondent Sheila MacVicar reports that, possibly even more telling about the shop video, is that the man in the video is wearing all-white, a color associated in Islam with death or mourning.
President Obama, speaking before a scheduled event in Washington, said, "It's difficult enough when we lose these brave Americans in battles overseas. It is horrifying that they should come under fire at an Army base on American soil."
"I would ask all Americans to keep the men and women of Fort Hood in your thoughts and prayers. We will make sure that we get answers to every single question about this horrible incident," Mr. Obama said.
Covering 339 square miles, Fort Hood is the largest active duty armored post in the United States. Home to about 52,000 troops as of earlier this year, the sprawling base is located halfway between Austin and Waco.
The base is home to nine schools - seven elementary schools and two middle schools - and all were on lockdown, said Killeen school spokesman Todd Martin.
Texas Department of Public Safety spokeswoman Tela Mange said Texas Rangers and state troopers were en route to Fort Hood to help seal the perimeter of the 108,000 acre base.
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.