Guantanamo Bay Naval Base, Cuba ? Khalid Sheikh Mohammed, the reputed mastermind of the Sept. 11 attacks, told a military judge at his arraignment Thursday that he welcomes the death penalty as a way to martyrdom and ridiculed the proceedings as an “inquisition.”

In his first public appearance since his capture five years ago, Mohammed wore dark-framed prison-issue glasses, a turban and a bushy, gray beard, and 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-Qaida’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. All five said they did not want attorneys and would represent themselves.

Their war-crimes tribunal is the highest-profile test yet of the military’s tribunal system, which faces an uncertain future. It also threatens to expose harsh interrogation techniques used on the men, who were in CIA custody before being transferred to Guantanamo in 2006.

A sound feed to journalists from the courtroom was turned off twice. The first time, a soldier told reporters 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 United States.

The sound was also turned off when another defendant discussed early days of his imprisonment. Judge Ralph Kohlmann said that in both cases sound was turned off because classified information was discussed.

The arraignment, in which no pleas were entered, indicated that hatred for the United States among some of the defendants remains at a boil.

One defendant said he deeply regrets not joining the hijackers who crashed passenger airliners into the World Trade Center, the Pentagon and a Pennsylvania field.

“I have been seeking martyrdom for five years,” said Ramzi Binalshibh, the alleged main intermediary between the 19 hijackers and al-Qaida leaders. “I tried for 9/11 to get a visa but I could not.”

Asked if he understands that he could be executed if found guilty, Binalshibh said: “If this martyrdom happens today, I welcome 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 he would not be represented by any attorneys. The other detainees quickly followed suit and said they too wanted to represent themselves.

One defense attorney said his client, Mustafa Ahmad al-Hawsawi, was pressured by the other four to snub his defense team. Kohlmann then barred the detainees from talking with each other.

As the judge closed the session, which lasted nearly 10 hours with breaks, he asked the defendants to rise but they refused. He said he would set a trial schedule later.

The U.S. 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. Binalshibh’s ankles were chained to the floor.