This court room sketch shows Maj. Nidal Malik Hasan during his court-martial today in Forth Hood, Texas. Hasan is representing himself against charges of murder and attempted murder for the 2009 attack that left 13 people dead at Forth Hood.

By NOMAAN MERCHANT

Associated Press

and PAUL J. WEBER

Associated Press

FORT HOOD, Texas - The Army psychiatrist accused in the 2009 shooting rampage at Fort Hood targeted fellow soldiers in a meticulously planned attack that included stockpiling bullets and researching Taliban leaders calling for jihad, a military prosecutor said today during the opening day of the long-awaited trial.

Maj. Nidal Malik Hasan spent time at a shooting range and purchased a pistol and extender kit to hold more ammunition before carrying out his plan to "kill as many soldiers as he could" while avoiding civilians, Col. Steve Henricks told jurors. The shooting, which killed 13 people and injured more than 30 others on the sprawling Texas military base, remains the deadliest mass shooting ever on a U.S. military installation.

Henricks alleged that Hasan didn't want to deploy after getting his orders about three weeks before the shootings, and that "he came to believe he had a jihad duty to murder to his fellow soldiers." The American-born Muslim later told a doctor at the base that, "'They've got another thing coming if they think they are going to deploy me,'" Henricks said.

But when it came time for him to speak, Hasan -- who is acting as his own attorney -- countered prosecutors' detailed portrait of the attack with a simple statement: "The evidence will clearly show that I am the shooter." But added that it wouldn't tell the whole story.

In writings and in previous court statements, Hasan indicated he wanted to argue that he carried out the shooting to defend the Taliban from American attacks -- but the judge denied that strategy. During his 2-minute opening statement Tuesday, he touched on his religion, saying: "We are imperfect Muslims trying to establish the perfect religion. ... I apologize for any mistakes I made in this endeavor."

His statements highlighted the complexity of the military's case. Hasan wanted to plead guilty to several counts of murder and attempted murder, but military rules prevent guilty pleas in death-penalty cases. Prosecutors are pursuing a death sentence, which are often overturned in military courts.

The trial is playing out amid high security at Fort Hood, where armed guards stood in doorways and 15-foot stacks of shock-absorbing barriers obscured the view of the courthouse. Jurors were told to prepare for a trial that could take months, and Hasan, who is in a wheelchair, needs regular breaks because he was paralyzed after being shot by officers responding to the shooting.

On the day of the attack, Hasan sat among his fellow soldiers preparing to deploy at a building on the sprawling Army base. He had masked the sound of his equipment by stuffing paper towels into the pockets of his cargo pants, Henricks said.

"All those fully loaded magazines do not clink, do not move, do not give him away," the prosecutor told jurors, all military officers, during his opening statement. "He sits among the soldiers he's about to kill with his head down."

Hasan tried to clear the area of civilians, even walking over to a civilian data clerk to tell her she was needed elsewhere in the building because a supervisor was looking for her. The prosecutor said the clerk thought that was odd but went anyway.

"He then yelled 'Allahu akbar!' and opened fire on unarmed, unsuspecting and defenseless soldiers," Henricks told the jury, noting that one of the soldiers who was killed had run after Hasan armed with only a chair.

When Hasan left the building, a civilian approached him and asked what was going on. Hasan told him not to worry about it, and the civilian "walks away from the encounter unscathed," the prosecutor said. Hasan allegedly told another civilian it was a training exercise and that he was carrying a paintball gun.

Hasan only shot at one civilian who tried to stop him, Henricks said.

Henricks also said Hasan picked the date of the attack - Nov. 5, 2009 - for a specific reason, though he didn't immediately reveal details.

The first witnesses called by prosecutors worked at the gun shop where Hasan purchased his equipment, but Hasan chose not to question them. Dressed in green Army fatigues, Hasan mostly looked down or straight ahead, occasionally leafing through paperwork with his right hand while seated at the defense table.

Numerous requests have delayed the trial for years, including a fight over Hasan's beard, which violates military regulations. The spat led to a stay shortly before his trial was expected to begin last year and the eventual replacement of the judge.

Hasan dismissed his attorneys earlier this year, and his brief opening statement on Tuesday mirrored his demeanor during jury selection last month when he did not speak often and asked only a few questions about religion.

Over the next several weeks, Hasan is expected to question witnesses and possibly present his own evidence -- which will likely turn the trial into a faceoff between the gunman and his victims.

On the witness stand will be many of the more than 30 people who were wounded, plus dozens of others who were inside the post's Soldier Readiness Processing Center. They've also said they saw Hasan shout "Allahu akbar!" -- Arabic for "God is great!" -- and opened fire on unarmed fellow soldiers.

The government has said that Hasan had sent more than a dozen emails starting in December 2008 to Anwar al-Awlaki, a radical U.S.-born Islamic cleric killed by a drone strike in Yemen in 2011.

Hasan has never denied carrying out the attack, and the facts of the case are mostly settled. But questions abound about how the trial will play out. How will Hasan question his victims? How will victims respond? How will his health hold up?

The defendant is paralyzed from the waist down. He requires 15- to 20-minute stretching breaks about every four hours, and he has to lift himself off his wheelchair for about a minute every half hour to avoid developing sores.

Staff Sgt. Alonzo Lunsford, who was wounded, is expected to testify. He said he looked forward to seeing Hasan, in a way.

"I'm not going to dread anything. That's a sign of fear," Lunsford said. "That man strikes no fear in my heart. He strikes no fear in my family. What he did to me was bad. But the biggest mistake that he made was I survived. So he will see me again."

But Staff Sgt. Shawn Manning said he dreaded the expected confrontation.

"I have to keep my composure and not go after the guy," said Manning, a mental health specialist who was preparing to deploy to Afghanistan with Hasan. "I'm not afraid of him, obviously. He's a paralyzed guy in a wheelchair, but it's sickening that he's still living and breathing."

AP National Writer Allen G. Breed and Associated Press writer Ramit Plushnick-Masti contributed to this report.