Story highlights Maj. Nidal Hasan was admitted Saturday to an Army hospital

He's in good condition and should be out within 48 hours, the military says

The military psychiatrist is accused of killing 13 people at Fort Hood, Texas, in 2009

The military psychiatrist accused of killing 13 people in a 2009 Fort Hood shooting spree has been admitted to an Army hospital for treatment of an undisclosed condition, the Army base said Monday.

Maj. Nidal Hasan was admitted Saturday to Carl Darnal Medical Center on the Army base in Texas and is expected to be released within 48 hours, Fort Hood's public affairs office said.

The military did not disclose why Hasan was in the hospital, citing federal government regulations against conveying patients' medical information. He was in "good condition" Monday, according to Fort Hood.

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His lead military attorney, Lt. Col. Chris Poppe, said only that his client wasn't suffering from a self-inflicted wound.

Hasan is accused of opening fire at the large Army post's processing center, where soldiers were preparing to deploy to Afghanistan and Iraq, in November 2009. The solo attack left 32 people wounded, in addition to the 13 killed, while Hasan himself was paralyzed from the waist down after police officers exchanged fire with him.

His court-martial tied to the shooting had been scheduled to start last month. But the Army Court of Criminal Appeals this month delayed its start indefinitely to determine whether his beard can be forcibly shaved during trial.

If convicted, Hasan could be sentenced to death.

A U.S.-born citizen of Palestinian descent, he was a licensed psychiatrist who joined the Army in 1997. He had been scheduled to deploy to Afghanistan before the killings, but had been telling his family since 2001 that he wanted to get out of the military.

Hasan is a Muslim who had told his family he had been taunted after the terrorist attacks of September 11, 2001. Investigations tied to the Fort Hood shootings found he had been communicating via e-mail with Anwar al-Awlaki, the prominent and radical Yemeni-American cleric killed by a U.S. drone attack in 2011.