WASHINGTON, November 7, 2009 (AFP) - A shooting spree blamed on a Muslim officer at a Texas military base has confronted President Barack Obama with two of his most pressing concerns: troop moral and inter-faith relations.

Like any US president faced with a similar national tragedy, Obama on Friday played the role of comforting a nation shocked at the bloody murder of 13 of its own. Appearing at the White House, the president paid tribute to victims of Thursday's Texas military base massacre, blamed on an embittered Muslim gunman.

But amid the anguish, Obama has been keen to offset the blow to troop moral and to head off an upsurge in anti-Muslim sentiment. His caution was evident at the White House on Friday, when he warned Americans against reaching hasty conclusions about Thursday's eruption of violence at the largest US military base in the world.

Authorities have said Nidal Hasan, an army psychiatrist, opened fire on fellow soldiers in a rampage that left 13 dead and 30 wounded. Hasan, who was shot by a female police officer, was hospitalized. Leaving defense officials and the FBI to investigate the motive for the attack, Obama ordered that flags be flown at half staff on the White House and federal buildings.

He is expected to attend religious service at Fort Hood ahead of a trip to Asia on Wednesday, his spokesman Robert Gibbs said. "The memorial service would be scheduled for the convenience of the families that suffered the tragic losses yesterday," Gibbs told reporters.

But for Obama the gruesome act raises the dual specter of military stress caused largely by the wars in Iraq and Afghanistan and the treatment of Muslim soldiers in the army.

That the suspected shooter was a Muslim who dealt with traumatized soldiers returning from the theater and was reportedly unhappy about his own imminent deployment to Afghanistan only heightened the shooting's poignancy. "Let's figure out what we need to know and go from there," said Gibbs, seeking to diffuse tensions.

Obama was said to have discussed the impact of the event on troop morale with his Secretary of Defense Robert Gates, amid record levels of depression and suicide. "Obviously, that's something that's on their minds," Gibbs said.

Gibbs indicated that the Fort Hood incident tapped into a crucial issue of troop stress confronting Obama as he mulls sending tens of thousands of additional troops to Afghanistan, Gibbs said. "I think that is certainly one of the things that the president will have to take into account in making any decision about resources in that region."