MADRID, Spain - Twenty-four Muslim men went on trial today as suspected members of an al-Qaida cell accused of using Spain as a staging ground to plot the Sept. 11 terror attacks.

The defendants - mostly of Syrian and Moroccan origin - sat on wooden benches in a cramped, bullet-proof chamber at a makeshift courtroom as the trial before a three-judge panel got under way.

Spain is only the second foreign country after Germany to try suspects in the suicide airliner attacks against the World Trade Center and the Pentagon.

The main suspect is Imad Yarkas, a 42-year-old father of six who, under the guise of being a used-car salesman, is alleged to have overseen a cell that provided logistical cover for Sept. 11 plotters like Mohamed Atta, believed to have piloted one of the two airliners that destroyed the World Trade Center.

The trial is the culmination of an eight-year investigation by anti-terrorism magistrate Baltasar Garzon, which determined that Muslim militants leading quiet lives as businessmen, laborers or waiters operated freely in Spain for years, allegedly recruiting men for terrorist training in Afghanistan, preaching holy war and laundering money for al-Qaida operations.

Two other suspects also are accused of planning the attacks. Moroccan Driss Chebli, 33, allegedly helped Yarkas arrange a July 2001 meeting in Spain attended by Atta and Sept. 11 coordinator Ramzi bin al-Shibh. Syrian-born Ghasoub al-Abrash Ghalyoun, 39, made detailed video footage of the World Trade Center and other landmarks while visiting the United States in 1997.

The other 21 on trial are charged with terrorism offenses but are not directly linked to the Sept. 11 attacks.