FORT HOOD, Texas -- The Army psychiatrist charged in the deadly 2009 Fort Hood shooting rampage has appealed a military judge's order to have his beard forcibly shaved before his murder trial.

Maj. Nidal Hasan's defense attorneys filed two appeals with the Army Court of Criminal Appeals this week. They say the federal Religious Freedom Restoration Act allows Hasan to keep his beard during trial.

Hasan says he grew a beard because his Muslim faith requires it.

The government has until Sept. 28 to file a response. The appeals court has postponed Hasan's murder trial until further notice.

After the court rules, further appeals could be made to the Court of Appeals for the Armed Forces.

Hasan faces the death penalty if convicted in the attack that killed 13 on the Texas Army post.

GALLERY: FORT HOOD SHOOTING
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  • Nidal Hasan

    FILE - This undated file photo provided by the Bell County Sheriff's Department via The Temple Daily Telegram shows Nidal Hasan, the Army psychiatrist charged in the deadly 2009 Fort Hood shooting. Hasan should be forced to shave his beard to avoid any potential jury bias in his pending murder trial, say some military experts and the judge overseeing his pending court-martial. (AP Photo/Bell County Sheriff's Department via The Temple Daily Telegram, File)

  • Nidal Hasan

    FILE - An April 9, 2010 file photo provided by the Bell County Sheriffs Department, shows U.S. Maj. Nidal Hasan at the San Antonio to Bell County Jail in Belton, Texas. Judge, Col. Gregory Gross, is to decide at a pretrial hearing Tuesday Aug. 14, 2012, whether to delay the trial of Hasan. (AP Photo/Bell County Sheriffs Department, File)

  • Nidal Malik Hasan

    FILE - The 2007 file photo provided by the Uniformed Services University of the Health Sciences (USUHS) shows Nidal Malik Hasan when he undertook the Disaster and Military Psychiatry Fellowship program. Hasan is charged in the fatal 2009 shooting rampage at Fort Hood which killed 13 people and injured more that 30 others. He faces the death penalty if convicted. (AP Photo/Uniformed Services University of the Health Sciences, File)

  • Maj. Laura Suttinger of the 467th Combat Stress Control Detachment shows a bracelet at a press conference Saturday, Oct. 30, 2010, in Madison, Wis. The bracelet commemorates soldiers who were killed on Nov. 5, 2009, at Fort Hood in Killeen, Texas, during a shooting rampage suspect Maj. Nidal Hasan. (AP Photo/Andy Manis)

  • FILE - In this Nov. 5, 2009 file photo, the entrance to Fort Hood Army Base in Fort Hood, Texas, near Killeen is seen. Eighty-three victims and family members in the worst mass shooting ever at a U.S. military installation are seeking $750 million in compensation from the Army, alleging that willful negligence enabled psychiatrist Maj. Nidal Hasan to carry out a terrorist attack at Fort Hood, Texas. (AP Photo/Jack Plunkett, File)