FORT HOOD, TEXAS — The Army psychiatrist accused in the Fort Hood shootings was charged with 13 counts of premeditated murder in the military's legal system, making him eligible for the death penalty if convicted, officials said Thursday.

Meanwhile, President Barack Obama ordered a review of all intelligence related to Maj. Nidal Malik Hasan and whether it was properly shared and acted upon within individual government agencies.

The announcement comes as members of Congress are pressuring for a full investigation in why Hasan was not detected and stopped. A Senate hearing on Hasan is scheduled for next week. The Senate Homeland Security Committee announced it is opening its own investigation this week.

U.S. Army Criminal Investigation Command spokesman Chris Grey said at a news conference that additional charges may be filed against Hasan.

Officials told The Associated Press before the news conference that it had not been decided whether to charge Hasan with a 14th count of murder related to the death of the unborn child of a pregnant shooting victim. The officials spoke on condition of anonymity because they were not authorized to speak about the case publicly.

Fort Hood officials declined to specify what the other charges against Hasan could be. Under a provision in the military code, a suspect can be charged with death of an unborn child, which is defined as a fetus at any stage of development, said Richard Stevens, a civilian attorney who handles military cases but is not involved in Hasan's case.

John Galligan, Hasan's civilian attorney, said his military co-counsel told him that charges were being read to Hasan in the hospital without his lawyers present.

Galligan said military officials had not notified him or sent him documents about any charges.

"What I find disturbing is that my client is in ICU, and he's 150 miles south of his defense counsel, and he's being served with the charges," he told The Associated Press. "Given his status as a patient, I'm troubled by this procedure and that I'm not there. I'm in the dark, and that shouldn't be the case. I am mad."

Grey said investigators believe Hasan was the lone gunman. Hasan was not at the Soldier Readiness Center for any pre-deployment activities when he allegedly opened fire last week, Grey said. The readiness center, parking lots and four other post buildings were still being treated as crime scenes, and the investigation remained open.

"We have a duty and obligation to protect the constitutional rights of everyone involved," Grey said.