FORT HOOD, US : A US military jury on Wednesday began deliberating the sentence for an army officer who killed 13 people in a 2009 shooting rampage at Fort Hood, after prosecutors called for his execution.

Major Nidal Hasan was convicted Friday of 13 charges of premeditated murder for the killing spree at the Texas base, which also left more than 30 others wounded.

In closing arguments in the sentencing phase of the trial, military prosecutors called for the jury of 13 officers to issue a rare death sentence for the 42-year-old onetime psychiatrist.

“He was trained as a doctor to save lives, but on November 5, 2009, he dealt death,” lead prosecutor Colonel Mike Mulligan told the court.

“He dealt no compassion, no understanding, he only dealt death.”

The widows and mothers of soldiers slain in the mass shooting - the worst ever on a US military base - sat in silence, occasionally capturing the glances of jurors as Mulligan recounted the stories of each of the dead.

Hasan, his eyes cast downwards throughout the hearing, opted not to address the jury, simply saying: “I have no closing statement.”

The jury can also choose to send Hasan to prison for life.

But if he gets the death penalty, the US-born Muslim of Palestinian descent would be the first member of the Army to receive such a sentence since the 2005 conviction of Hasan Akbar, who killed two in an attack on fellow soldiers in Kuwait in 2003.

Many legal experts had expected Hasan, who is representing himself, to use the trial as a platform to espouse radical Islamic views.

He instead has put up virtually no defense at all.

Hasan has called no witnesses, entered scant evidence and has only made one statement to the jury, telling the court at the outset of the trial, “I am the shooter.”

“I’ve never seen anything like this before. This is quite unprecedented,” said Richard Rosen, a military law expert at Texas Tech University.

On November 5, 2009, Hasan opened fire at a medical processing facility in the sprawling Fort Hood base that serves as a staging point for soldiers to deploy to combat zones.

Twelve of the dead and 30 of the wounded were soldiers. Hasan was himself shot by a civilian police officer who responded to the attack and he is now partially paralyzed.

He initially attempted to defend the rampage as a pre-emptive attack on soldiers who would strike Muslims in Iraq and Afghanistan.

But the presiding judge, Colonel Tara Osborn, disallowed that tactic, stating it held no legal merit.

Since Osborn’s ruling, Hasan has remained quiet in court, while strategically leaking documents to media outlets.

In a letter to AFP, he stated religion was his motive in the attack, and criticized US foreign policy he believes aims to topple Islamic governments to install secular leadership.

Many, including the Army attorneys advising Hasan, believe his lack of action in court shows he is pursuing a death sentence.

In an Army mental health report from 2010, Hasan said a death sentence would make him a martyr.

But Mulligan said Wednesday: “He will never be a martyr, because he has nothing to give. (...) This is not his gift to God, it is his debt to society.”