Spain for the first time issued international arrest warrants Wednesday in the Madrid train bombings (search), seeking six suspects in a widening probe into the worst terrorist attack in Spanish history.

The names and photographs of the warrants for five Moroccans and a Tunisian were distributed by the Interior Ministry. They included two brothers of Naima Oulad Akcha, the only woman charged in the case so far, a court official said.

The warrants were sent internationally and not specifically to Britain, Morocco and France, contrary to earlier reports, a court official said.

Earlier a government official erroneously said that one of the warrants was for Abdelkrim Mejjati, a 36-year-old Moroccan who was convicted in absentia in the deadly bombings in Casablanca last year, which killed 33 people and 12 homicide bombers. Mejjati is wanted by the FBI in connection with possible terrorist threats against the United States.

Spanish police have 19 people in custody -- 11 Moroccans or Moroccan-born Spaniards, two Indians, two Spaniards and three Syrians. The nationality of one suspect, whose arrest was announced Wednesday, was not released.

Fourteen of the suspects have been charged with mass murder or collaborating with or belonging to a terrorist group.

Interior Minister Angel Acebes on Tuesday identified the Moroccan Islamic Combatant Group (search) as the main focus of investigation in the March 11 bombings in Madrid, which killed 191 people and injured more than 1,800 others. That extremist group is a forerunner of Salafia Jihadia, which Morocco blamed for the Casablanca bombings.

At least five members of the Combatant group, including alleged leaders Nouredine Nfia and Salahedine Benyaich, trained in Al Qaeda (search) camps in Afghanistan between 1999 and 2001, Moroccan officials said.

Spanish investigators have analyzed a videotape in which a man claiming to speak on behalf of Al Qaeda said the group carried out the Madrid attacks in reprisal for Spain's backing of the U.S.-led war in Iraq.

In the investigation, Moroccan Mustapha Ahmidam and Antonio Toro Castro, the brother-in-law of a Spaniard charged with supplying dynamite to the bombers, were questioned by the judge Wednesday.

Ahmidam was released, and Castro was ordered to return to court on Friday.

Another Moroccan, Fouad Almorabit, was re-arrested Wednesday.

The radio station Cadena Ser said one of the suspects who went before the judge told him the attack was motivated by the occupation of Iraq and that Britain, Spain and the United States are held responsible.

Two Syrians arrested Tuesday, Walid Altaraki and Mohamad Badr Ddin Akkad, are set to appear Thursday.

Interior Minister Acebes said Tuesday said some of the chief perpetrators were among those in custody.