US base shooting suspect in coma, shifted for security reasons

US military psychiatrist Major Nidal Malik Hasan, responsible for a horrific shooting spree that left 13 dead, was in coma and transferred from a civilian to an army hospital for security reasons, officials said.

Hasan is said to be in critical but stable condition, attached to a ventilator, while many of his victims are still fighting for their lives in hospitals. His comatose condition is frustrating attempts by investigators to work out the motive behind his killings.

"The military officer suspected in the shooting deaths of 13 people here was transferred from a civilian to a military hospital in part for security reasons," a military official said.

So far, the investigators are trying to unravel many unknowns about the man they say is responsible for the worst killing on a US military base, most of all his motive.

Though hampered by being unable to question him, investigators have seized his home computer during search of his apartment in Killeen in Texas and looked at his garbage to learn what motivated the suspect, who lay in coma, shot four times by a gallant lady police officer in the frantic bloodletting.

Hospital sources said some of his wounds are extremely serious and he might not survive and this possibility is lending urgency to investigations.

Twenty-three of the 30 injured victims remained hospitalised, about half of them in intensive care unit. The commander of the base praised the sharp response to the shooting rampage of the Major, saying that the reaction had saved precious lives.

The injured have been dispersed in Texas' various hospitals with officials saying that several were still "at significant risk".

US Army's chief of staff Gen George Casey said security at all US military bases had been ramped up and he was worried about a backlash against thousands of Muslim soldiers serving in uniform.

Seeking to reassure the nation shaken by the mass shooting, Obama said that the military training was designed to keep US forces safe abroad and had prevented larger casualties at Fort Hood and ended the rampage.

In his weekly radio broadcast, the president praised the heroism that ended the gunfire at the country's largest military base.

"They are Americans of every race, faith and station. They are Christians and Muslims. Jews and Hindus and non-believers," Obama said.

"They are descendants of immigrants and immigrants themselves. They reflect the diversity that makes America," Obama said reminding Americans of their diversity in an apparent move to calm tensions.

The bodies of those killed in the shooting spree at the base will be taken to the same mortuary that handles fallen soldiers from the wars in Afghanistan and Iraq, the Pentagon said.

A C-17 cargo aircraft carrying the remains of the 13 victims of the rampage will fly them to Dover Air Base for solemn ceremonies which will be attended by president Barack Obama.

But on the Ground Zero, investigators kept up their hunt for what could have driven the Muslim officer in carrying out the carnage.

Soldiers are said to have heard the suspect shout "Allahu Akbar" – Arabic for "God is great" – before opening fire at the sprawling military complex.

Army Col John Rossi, deputy commander at Fort Hood, said the officer had fired more than a 100 rounds and that his weapon, an F-5.7 pistol, was not an military issue, but "privately-owned weapon purchased locally".

Now authorities are figuring out if Hasan's rampage was driven by mental breakdown or ideological rage, various links to extremist websites are being examined closely.

Hasan, who was about to be posted in Afghanistan called the war on terrorism "a war against Islam," according to a doctor who was in a graduate programme with him.

"He was a ticking time bomb".

While studying for a masters degree in public health in 2007, Hasan used a presentation for an environmental health class to argue that Muslims were being targeted by the US anti-terror campaign, said Val Finnell, a classmate.