In his first public appearance since his capture five years ago, Mohammed wore thick glasses, a turban and a bushy, gray beard, and he was noticeably thinner - a stark change from the slovenly man with disheveled hair, unshaven face and T-shirt from the widely distributed photograph after his seizure in Pakistan.
He and four other detainees accused of plotting al Qaeda's 2001 attack were at turns cordial and defiant at their arraignment, the first U.S. attempt to try in court those believed to be directly responsible for killing 2,973 people in the bloodiest terrorist attack ever on U.S. soil.
The arraignment is the highest-profile test yet of the military's tribunal system, which faces an uncertain future at Guantanamo. It also could expose harsh interrogation techniques used on the men, who were in CIA custody before being transferred to Guantanamo in 2006.
The government is seeking the death penalty for all five defendants, who sat at separate tables with their defense teams in a high-tech courtroom on this U.S. Navy base.
Mohammed, who has confessed to the 9/11 attack, the beheading of American journalist Daniel Pearl and a chilling string of other terrorist plots, was careful not to interrupt Judge Ralph Kohlmann. He lost his composure only after the Marine colonel ordered several defense attorneys to keep quiet.
"It's an inquisition. It's not a trial," Mohammed said in broken English, his voice rising. "After torturing they transfer us to inquisition-land in Guantanamo."
Mohammed openly made hand signals and seemed to be directing his co-defendants who sat single file behind him, reports CBS News correspondent Bob Orr.
The former No. 3 al Qaeda leader explained he believes only in religious "Sharia" law and railed against President Bush for waging a "crusade war." The judge, wearing a crewcut and black robes, warned Mohammed that he faces execution if convicted of organizing the attacks on America. But Mohammed said he welcomed the death penalty.
"Yes, this is what I wish, to be a martyr for a long time," Mohammed declared. "I will, God willing, have this, by you."
The five men appeared for the joint arraignment at a high-tech courtroom set up on an abandoned airfield on this U.S. Navy base. The five defendants, who were dressed in white, had no handcuffs and sat at separate tables with their defense teams.
Defendant Ramzi Binalshibh, the alleged main intermediary between the 19 hijackers and al Qaeda leaders, had his ankles chained to the floor.
The military is trying to minimize the chance that classified information that would endanger Americans will come out, including delaying closed-circuit video of the proceedings by 20 seconds.
A sound feed to journalists from the courtroom was turned off at one point, and a soldier said it was because a detainee was discussing a medication he had been given, which was a privacy issue. But his defense attorney, Navy Cmdr. Suzanne Lachelier, told The Associated Press later that the prisoner had been discussing his five years as a prisoner of the U.S.
The arraignment indicated that hatred for the United States among some of the defendants remains at a boil.
Binalshibh said he wanted to be a hijacker and be killed on 9/11, reports CBS News producer Rob Hendin.
When asked if he understood that if convicted, the penalty sought by the U.S. government could include a death sentence, Ramzi responded in Arabic: "I've been seeking martyrdom for five years. I tried for 9/11 to get a visa, but could not. I tried to get a visa. If this martyrdom happens today, so be it.. God is great, God is great, God is great."
Calmly propping his glasses on his turban to peer at legal papers, Mohammed grinned at times and insisted that he would not be represented by any attorneys.
Two other detainees quickly followed suit and said they too wanted to represent themselves - Binalshibh and Waleed bin Attash, who allegedly selected and trained some of the hijackers.
"It hardly comes as any surprise that after holding individuals in solitary confinement for five years and subjecting them to torture, these detainees would reject the legal system and offers to represent them," said Anthony D. Romero, Executive Director of the American Civil Liberties Union in New York.
Mohammed is one of three Guantanamo prisoners who the CIA says were subjected to particularly harsh interrogation techniques, including waterboarding - a technique that gives the sensation of drowning and is considered torture by human rights groups.
He is the most valuable al Qaeda official in U.S. custody and the central figure in a trial that will test the Pentagon's military tribunals, which have faced repeated legal setbacks, including a Supreme Court appeal on the rights of Guantanamo detainees that could produce a ruling this month halting the proceedings.
Defense attorneys blasted the military commissions, which were declared unconstitutional by the Supreme Court in 2006 before being resurrected in an altered form by Congress and President Bush.
"I think the American people, if they ... understood the ramifications in the long term to our Constitution, to their Constitution, I think they would be ashamed," Lachelier, the attorney for Binalshibh, said outside the heavily guarded courtroom.
She tried to raise another pending Supreme Court decision in the courtroom, on the benchmark when defendants can be allowed to represent themselves, but Kohlmann told her to keep quiet.
"What part of 'no' do you not understand?" the judge said, peering down from the bench. "Sit down."
Lachelier said the defense learned Wednesday that Binalshibh is on "psychotropic medication." The defendant said he was forced to take medication.
Binalshibh's civilian attorney, Thomas Durkin, said the men should be tried in U.S. federal courts.
"We have had many terrorism cases in our federal court system," Durkin said. "I think it is a shame that for whatever reason the Bush administration has put on what we think is a show trial."
The military commissions plan to allow coerced testimony, which has drawn widespread criticism, although evidence obtained by torture is not allowed. Attorneys for Mohammed have said they will challenge evidence obtained during his custody in secret CIA prisons, where the U.S. has said he was waterboarded.
Air Force Brig. Gen. Tom Hartmann, a top tribunal official, told reporters it was up to the judge to determine whether to allow statements obtained during waterboarding as evidence. Hartmann said waterboarding has not officially been classified as torture.
Mohammed said he was tortured after being captured in Pakistan in 2003 but didn't elaborate, indicating he understood he should not discuss it in the courtroom.
"I can't mention about the torturing," said Mohammed, who received an engineering degree from North Carolina Agricultural and Technical State University. "I know this is the red line."
The five defendants spoke with each other in Arabic, appeared to pass notes to each other and at one point looked back and chuckled at reporters watching from behind a courtroom window.
All appeared to be in robust health except for Mustafa Ahmad al-Hawsawi, who allegedly selected and trained some of the 19 hijackers. He looked thin and frail and sat on a pillow on his chair.
The other defendants are Ali Abd al-Aziz Ali, known as Ammar al-Baluchi, a nephew and lieutenant of Mohammed, and Mustafa Ahmad al-Hawsawi, a Saudi, who allegedly helped finance the hijackers.
About 35 journalists watched on closed-circuit TV in a press room inside a converted hangar, while two-dozen others watched through a window from an adjacent room. No photographs were allowed in the courtroom, but a