MADRID (Reuters) - Spain's Interior Minister Angel Acebes is set to announce the arrest of at least four Muslims in connection with a series of deadly bombings in Madrid, the web site of newspaper El Mundo says.

According to El Mundo, they've arrested three Moroccans and two East Indians, and they're questioning two Spaniards of East Indian ancestry. They had some sort of tie to the prepaid cellular phone found with the unexploded backpack bomb.

'Morocco struggles to tamp down radical Islam' has some background. It mentions the Salafia Jihadia group, which was responsible for the May 2003 bombings in Casablanca. The supposed masterminds of that group were arrested a few months before the bombings. 'Cyanide plot suspects linked with terror groups' mentions Moroccans arrested in Italy; they're suspected members of two other AQ linked groups. They apparently had cyanide and were trying to dig a tunnel into the U.S Embassy. This editorial mentions the Algerians arrested in London with ricin.

'Suspected Moroccan terrorists 'had map of London' says: "They were detained after officers found a kilogram of explosives and several maps in a building where the men were staying in the Rovigo, near Venice... Reports said the maps included plans of Padua's Basilica del Santo, the Nato base in Verona and London... A religious leader of Rovigo's Muslim community was among those arrested..."

This page has a chronology of arrests of Muslim terrorists in Spain.

The AP report 'Al-Qaida's tentacles sweep through nearly every major attack since Sept. 11' says:

- MOROCCO: Of the more than 900 people arrested after five nearly simultaneous suicide attacks on Jewish and Spanish targets in Casablanca on May 16, the government said 100 told interrogators they received training in Afghanistan. At trial, 20 confessed openly to passing through the Afghan camps, including Nouredine Nfia, alias Abu Mouad, who admitted in court to going to Afghanistan ''for combat training against the enemies of Islam and apostates.''

The prosecution claimed that Nfia met personally with al-Qaida leader Osama bin Laden and trained at the al-Farouq camp near the eastern Afghan city of Khost. The Moroccan government says it is certain of a link between the homegrown Salafiya Jihadia group accused in the bombings and al-Qaida. Moroccan officials say some 300 so-called ''Moroccan Afghans'' are believed to have returned home from the camps...