Houston: A US Army psychiatrist, accused of the shooting rampage at a military base nearly four years ago, on Tuesday admitted to the attack that killed 13 people, calling himself a `mujahideen` in a short and unrepentant opening statement at his trial.
Major Nidal Malik Hasan admitted on Tuesday to opening fire on fellow soldiers at the Fort Hood military base in Texas, as he took charge of his own defence at a high-profile trial.
But Hasan also cautioned that the evidence wouldn`t tell the entire story.
"The evidence will clearly show I am the shooter," declared Hasan, who has fired his lawyers and is representing himself, in his opening statement.
Hasan, who has previously admitted to killing the 13 people and wounding 32 others in the 2009 attack at Fort Hood, faces the death penalty if convicted.
However, he added, "Witnesses will testify that war is an ugly thing. Death, destruction and devastation are felt from both sides, from friend and foe. Evidence from this trial will only show one side. I was on the wrong side, but I switched sides".
The court-martial began under heavy security on Tuesday.
The 42-year-old Hasan, shot by a civilian police officer and paralysed from the waist down after the rampage, is confined to a wheelchair.
He has admitted to the 2009 rampage, but was prohibited by a military judge from entering a guilty plea because prosecutors are pursuing the death penalty.
He was about to be deployed to Afghanistan when the massacre happened.
The attack jolted the US military and prompted calls for stronger safeguards against internal security threats and "homegrown" terror attacks.
Nearly four years after being attacked in what should have been the safety of a protected base, survivors are steeling themselves to be cross-examined by Hasan, the man who shot them.
Born in the eastern US state of Virginia to Palestinian parents, Hasan joined the Army in 1995.
It was during a residency at Walter Reed Army Medical Center from 2003 to 2006 that Hasan first exhibited signs of radical Islamic views, according to an FBI report entitled "A Ticking Time Bomb".
Hasan attended a mosque where radical US-born cleric Anwar al-Awlaki -- a key figure in al Qaeda in the Arabian Peninsula until his death in a 2011 drone strike in Yemen -- worked in 2001.
Hasan has managed to delay the trial with various legal manoeuvres and a lengthy battle over whether he could violate military rules by wearing a beard.
Judge Colonel Tara Osborn has estimated the trial could last anywhere between one and four months.
More than 250 witnesses are set to testify against Hasan, including family members of each of those killed in the shooting and the soldiers and civilians who were wounded.
Hasan has said he only intends to call two witnesses in his defence.