FORT HOOD, Texas (AFP) - An army psychiatrist accused of massacring 13 people at Fort Hood has once again lost a bid to have the death penalty taken off the table, a military judge ruled on Wednesday.

Colonel Tara Osborn denied the request in a hearing on the sprawling Texas army base where Major Nidal Hasan is accused of going on a shooting spree in 2009 that also wounded wounding 32 people.

Hasan, who was paralysed after being shot in response to the attack, has attempted to plead guilty before. He had his request denied because prosecutors were unwilling to waive the death penalty, and military law does not permit people to plead guilty to a capital offence.

Col Osborn has taken over as judge in the case after Colonel Gregory Gross was removed over questions of his impartiality. Col 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.

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