A new trial date of July 1 has been set for the US Army psychiatrist accused of massacring 13 people at Fort Hood in 2009, a military judge ruled Thursday.

Major Nidal Hasan, who faces the death penalty, is accused of going on a shooting spree that also wounded 32 people.

The shooting jolted the US military and prompted calls for stronger safeguards against possible internal security threats and "homegrown" terror attacks.

The FBI alleges Hasan had contacts with firebrand US-born cleric Anwar al-Awlaqi, a key leader of Al-Qaeda in the Arabian Peninsula who was killed in a 2011 drone strike.

The Yemeni-based cleric was also believed to have been instrumental in planning the botched plot by a Nigerian student dubbed the "underwear bomber" who tried to blow up a US-bound airliner on December 25, 2009.

Hasan, who was born in Virginia to Palestinian parents and raised in the eastern US state, had attended a mosque in 2001 where Awlaqi worked and is believed to have continued to communicate with the radical cleric.

Set to deploy to Afghanistan weeks after the massacre, Hasan was shot by police officers as they tried to halt the carnage. He was left paralyzed from the neck down.

Hasan has attempted to plead guilty but the request was denied because prosecutors were unwilling to waive the death penalty, and military law does not permit people to plead guilty to a capital offense.

Colonel Tara Osborn, who took on the case after the original judge was removed over questions of impartiality, said in a hearing she would like jury selection to begin on May 29, with the trial penciled in for a July 1 start.

Colonel Gregory Gross had ordered Hasan to appear in court clean-shaven in accordance with military rules. Hasan refused, arguing he had a right to keep his beard as an expression of his Muslim faith, and appealed the order.

The argument over Hasan's beard held up his court-martial, which was originally due to get under way at Fort Hood in August 2012.