A dispute between two soldiers spiraled into a bloody attack at Fort Hood, Texas, that left four people dead and more than a dozen wounded Wednesday afternoon near a medical building, according to preliminary law enforcement reports. The gunfire sent tremors of fear across a sprawling Army base that was the site of one of the worst mass shootings in U.S. history less than five years ago.
Many basic details about the shooting remained unclear in the chaotic hours after the first calls for help, including what caused the soldiers' fight, but senior U.S. law enforcement officials said the incident did not appear to be linked to any foreign terrorist organizations. The shooter was among those who died, the officials said, apparently by his own hand.
The officials identified the shooter as Army Spec. Ivan Lopez, 34, a military truck driver, who was dressed in his standard-issue green camouflage uniform. The shooting occurred close to the building that houses the Army's 1st Medical Brigade on the vast central Texas post.
The shooting was the third major gun attack at a U.S. military installation in five years. A federal government contractor went on a shooting rampage at the Washington Navy Yard in September of last year, leaving 12 people dead. In November 2009, Army Maj. Nidal Hasan opened fire on a group of soldiers at Fort Hood preparing to deploy to Iraq and Afghanistan, killing 13 people and wounding more than 30.
President Barack Obama said he was "heartbroken that something like this might have happened again." Speaking during a fundraising trip to Chicago, he pledged "to get to the bottom of exactly what happened."
Mr. Obama reflected on the sacrifices that troops stationed at Fort Hood have made -- including enduring multiple tours to Iraq and Afghanistan. "They serve with valor. They serve with distinction, and when they're at their home base, they need to feel safe," he said. "We don't yet know what happened tonight, but obviously that sense of safety has been broken once again."
In the wake of the Navy Yard shooting, Defense Secretary Chuck Hagel ordered a series of security changes at military installations, including more rigorous screening of personnel and the creation of an analysis center to examine "insider threats."
"When we have these kinds of tragedies on our bases, something's not working," he said Wednesday evening during a visit to Hawaii. "We will continue to address the issue. Anytime you lose your people to these kinds of tragedies, it's an issue, it's a problem."
Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, said many questions remained about the shooting, but that a principal initial focus was to support the victims and their families. "This is a community that has faced and overcome crises with resilience and strength," he said in a statement.
Dozens of ambulances and law enforcement vehicles converged on the scene after the shooting.
The injured were taken to Darnall Army Community Hospital at Fort Hood and other local hospitals. Chief medical officer Glen Couchman at Scott and White Hospital in Temple, Texas, said the first four people admitted there had gunshots to the chest, abdomen, neck and extremities, and that their conditions ranged from stable to "quite critical."
The base was placed on lockdown for much of the afternoon, with loudspeakers across the facility urging people to shelter in place. The order applied to thousands of families that live on the post. The order was lifted later in the evening, once law enforcement authorities had determined that a sole gunman was responsible for the shooting.
With the exception of military police officers, soldiers on Fort Hood and all other U.S. military installations are not armed or permitted to carry privately owned firearms. The restrictions on personal weapons were expanded in the wake of the 2009 massacre and an epidemic of suicides on Fort Hood.
Hasan was convicted of multiple counts of murder last year and sentenced to death. He is on death row at the military prison at Fort Leavenworth, Kan.
Associated Press contributed.