Twenty-four suspected Al Qaeda members went on trial Friday, including the group's alleged ringleader in Spain and two associates accused of aiding one of the Sept. 11 suicide pilots who flew a jetliner into the World Trade Center (search).

The proceedings were Europe's biggest trial of alleged Al Qaeda (search) militants and made Spain only the second country after Germany to try suspects in the attacks that killed nearly 3,000 people on Sept. 11, 2001. The only man charged in the United States, Zacarias Moussaoui, said he would plead guilty Friday to charges tied to the attacks.

In a sometimes feisty appearance, the lone native-born Spaniard among the 24 Muslim defendants said he neither supported nor rejected Al Qaeda leader Usama bin Laden (search) but insisted that he himself rejected all forms of terrorism.

"Muslims are not terrorists," said Luis Jose Galan, 39. "All we want is to live in peace."

The lead defendant is Syrian-born Imad Yarkas, a 42-year-old father of six who allegedly directed a terrorist cell that provided logistical cover for Sept. 11 plotters, including Mohamed Atta, who is believed to have piloted one of the two planes that destroyed the twin towers in New York. Yarkas is expected to testify next week.

Lawyers for at least one defendant say they might seek testimony from terrorism suspects in U.S. custody. The only person convicted of involvement in the Sept. 11 plot — Mounir el Motassadeq (search) in Germany in 2003 — had the verdict overturned when an appeals court ruled his trial was unfair because the U.S. did not produce such testimony. He is being retried.

"It is very possible we will seek testimony from persons held in the United States," said Manuel Tuero, lead attorney for the suspected financial brains behind the Madrid cell, Mohamed Ghaleb Kalaje Zouaydi. "We'll have to see how the trial goes," he said.

Yarkas's lawyer, Jacobo Teijelo, said he would not make such a motion.

Among other things, Yarkas is charged with helping arrange a July 2001 meeting in Spain between Atta and Sept. 11 coordinator Ramzi bin al-Shibh, who is now in U.S. custody. Teijelo said it would pointless to seek testimony from al-Shibh to show the meeting did not take place. "A negative fact cannot be proven," he said in an interview.

The trial opened just over a month after the first anniversary of Spain's own brush with alleged Al Qaeda terrorism — bombings on commuter trains in Madrid that killed 191 people.

The Socialist government elected after the March 11, 2004 attack says it was probably prompted not by the presence of Spanish troops in Iraq — as asserted by militants who claimed responsibility in videotapes — but rather was revenge for the arrests of Muslim militants ordered by magistrate Baltasar Garzon in November 2001. Many of those arrested went on trial Friday.

An eight-year investigation by Garzon concluded that Muslim extremists leading quiet lives as businessmen, laborers and waiters operated in Spain for years, recruiting men for terrorist training in Afghanistan, preaching holy war and laundering money for Al Qaeda.

Bin Laden was among those indicted by Garzon, but Spanish law does not allow trials in absentia for terrorism cases.

Prosecutors are seeking prison terms of nearly 75,000 years each for Yarkas and two other key suspects accused of helping plan the Sept. 11 attacks, although the law limits the maximum time they could serve for a terrorism conviction to 40 years.

The 21 other defendants are charged with terrorism, illegal weapons possession and other offenses not related to the Sept. 11 plot.

The trial is the biggest of Al Qaeda suspects in Europe. A Turkish court is trying 69 people accused of involvement in November 2003 bombings that killed 60 people at two synagogues, the British consulate and a London-based bank in Istanbul, an attack that prosecutors say was orchestrated by suspected members of an Al Qaeda cell.

As the trial opened, all but one of the mostly Syrian and Moroccan defendants sat on wooden benches in a cramped, bulletproof chamber in the makeshift courtroom. Tayssir Alouny, a reporter for Al-Jazeera television who is the only defendant free on bail, was allowed to sit in the courtroom's main section because of a heart condition.

Galan, who is accused of illegally possessing weapons and belonging to Al Qaeda, was questioned by a prosecutor and the chief of the three-judge panel.

He acknowledged knowing some of the defendants as well as others indicted in the case who are fugitives, but said that was only because they went to the same Madrid mosques.

Asked about a shotgun, pistol and other weapons found in his Madrid apartment after his arrest in 2001, Galan said they were for target practice. "I have never used a weapon against a person or animal," he said.

He also played down a photograph showing him clothed as a Muslim freedom fighter and holding a rifle, saying that members of his family often dress in costumes.

Galan, who allegedly attended a terrorist training camp in Indonesia, was questioned about an e-mail he received from another suspect asking that Galan send weapons.

Galan said anyone could send him an e-mail "asking for the atomic bomb. So what?"

During a break, the defendants chatted animatedly, smiled and appeared to wave at someone through a wall of frosted glass on one side of the chamber.

Police armed with submachine guns and shotguns stood guard outside the courthouse, where the handcuffed defendants were delivered by vans behind a tall iron fence and were escorted inside. The trial is expected to last two to four months in the squat, red-brick building on the outskirts of Madrid.

Besides Yarkas, two other suspects are accused of helping the Sept. 11 plot:

— Driss Chebli, a 33-year-old Moroccan who allegedly helped Yarkas arrange the meeting in July 2001 at which Atta and al-Shibh planned final details of the attack.

— Syrian-born Ghasoub al-Abrash Ghalyoun, 39, who is charged with making videotapes of the World Trade Center and other U.S. landmarks in 1997 that were used to plan the attacks.