May 11, 2009 -- An American soldier suspected of killing five U.S. soldiers at a clinic at Camp Liberty today had been disarmed earlier after a dispute at the facility but came back with another weapon, a Defense official told ABC News.
The soldier, who is in custody, had gone to the clinic earlier in the day and got into a verbal altercation with someone there, the official said, speaking on condition of anonymity.
After the soldier left the clinic, someone in his chain of command took away his personal weapon for his own protection because he was in an unstable situation, the official said.
The soldier later obtained another weapon, however, and returned to the clinic.
Employees of the stress clinic near the Baghdad airport, as well as those seeking psychological treatment, were among the dead, officials told ABC News.
An Army official also said four others are wounded, including the alleged shooter. It is not yet clear if his wounds were self-inflicted or if he was shot by someone else.
ABC News has also learned the alleged shooter was on his third deployment and was recently referred for mental health issues, though he had not previously sought help for combat stress, according to a senior Defense official.
A February 2008 study by the U.S. Army Medical Command found that male noncommissioned officers on their third or fourth deployments were more than twice as likely to be suffering from mental health issues than those on their first deployment.
Today Defense Secretary Robert Gates said the deaths at Camp Liberty will receive the highest level of attention from the U.S. government.
"We are still in the process of gathering information on exactly what happened," Gates said this afternoon. "But if the preliminary reports are confirmed, such a tragic loss of life at the hands of our own forces is a cause for great and urgent concern. And I can assure you that it will get this department's highest priority attention."
"Any time we lose one of our own, it affects us all," said Multi-National Corps Iraq spokesman Col. John Robinson in a Monday statement. "Our hearts go out to the families and friends of all the service members involved in this terrible tragedy."
Eleven U.S. Deaths in Iraq This Month
White House spokesman Robert Gibbs said President Obama would meet with Gates this afternoon about the shooting.
"He was shocked by the news of this incident and will press to ensure that we fully understand what happened at the clinic and that we are doing everything we can to ensure that our men and women in uniform are protected," Gibbs said.
There's no word on which unit the soldiers belonged to. The incident is under investigation.
More information is expected to come after the families of those involved in the incident are notified.
It's not the first time a U.S. soldier has been suspected of harming his peers. In March 2003, Army sergeant Hasan Akbar killed two and wounded 14 others in a grenade attack in Kuwait in the days leading up to the start of the second Iraq War. He was later convicted and sentenced to death.
Eleven U.S. service members have been killed or died in Iraq in the month of May, including those who died in the incident at Camp Victory.
Sunday another soldier was killed in the southern city of Basra during an attack against his patrol.
ABC News' Mazin Faiq, Kate Barrett and James Hill contributed to this report.