The US army psychiatrist accused of killing 13 in a 2009 shooting spree at a Texas base will not be granted any more trial delays after electing to represent himself, a judge ruled Tuesday.

Colonel Tara Osborn set jury selection to begin July 9 with the court-martial starting on August 6.

Major Nidal Malik Hasan, 42, could face the death penalty if convicted of opening fire at a soldier processing center where hundreds of soldiers were preparing to deploy to Iraq and Afghanistan.

He is also accused of wounding 32 people during the Fort Hood massacre -- people Hasan will now be able to cross-examine in court now that he is representing himself.

He has managed to delay his trial with various legal maneuvers and a lengthy battle over whether he could violate military rules by wearing a beard.

He raised the possibility of a further delay l ast month by firing his lawyers just days before jury selection was set to begin and then requesting a three-month delay to prepare his defense.

Hasan told the judge he needed more time because he planned to shift to a "defense of others" strategy, explaining that the shooting was aimed at protecting the Taliban in Afghanistan.

Osborn ruled Friday that the defense strategy had no merit and could not be presented at trial. She offered him more time to prepare a different defense but Hasan declined and withdrew his request.

Hasan has told the court he would like to plead guilty to all charges. However, US military law prevents a soldier from pleading guilty to capital charges unless the death penalty is waived.

The November 2009 incident is the worst shooting on a military base in US history. It shocked the military and led to an outcry for greater security from "homegrown" terror acts.

An FBI review showed Hasan had been in contact with the US-born cleric Anwar al'Awlaqi, a key figure in Al-Qaeda in the Arab Peninsula who was killed in a 2011 drone strike in Yemen.

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.

Hasan exchanged emails with Awlaqi in the months leading up to the shooting in which he questioned the morality of killing soldiers if they intended to attack Muslims. Awlaqi later called Hasan a hero.

His attack in part inspired another army soldier to plot a thwarted bombing in the Texas town surrounding the large military base in 2011. That private has since been tried and sentenced to life in prison.