Spanish police on Thursday arrested 13 men accused of harboring Islamic extremists, including several suspects in the Madrid terror bombings of 2004, and helping them flee the country, the Interior Ministry said.

Police made the arrests in pre-dawn raids in four northeastern towns near Barcelona. Raids also occurred in Madrid and Algeciras in the south. At least 8 of the detainees are Moroccan. The identities of the rest were not immediately provided.

The arrests stemmed from a 2005 police operation during which Spain broke up a terror cell that allegedly recruited people to stage suicide attacks against U.S.-led forces in Iraq and other targets set by Al Qaeda, the ministry said in a statement.

The 13 men arrested Thursday are suspected of giving shelter to Islamic extremists, including at least five suspects in the March 11, 2004, train bombings that killed 191 people in Madrid, and helping them to flee the country.

Muslim militants claimed responsibility for the Madrid attack, saying they had acted on behalf of Al Qaeda to avenge the presence of Spanish peacekeeping troops in Iraq. However, Spanish authorities say they have found no evidence that Al Qaeda ordered or financed the attacks.

Spanish investigators have said one of the fugitive suspects in the Madrid attacks, Moroccan Mohamed Afalah, is believed to have died in a suicide attack in Iraq in 2005.

A confidential police report quoted in Spanish newspapers has said another fugitive, Daoud Ouhnane of Algeria, died in Iraq while fighting coalition forces.

Since the Sept. 11, 2001, terror attacks in New York and Washington, Spanish police have arrested hundreds of Islamic terrorism suspects, many in connection with the Madrid attack.

In recent years police also have focused on cells suspected of recruiting mujahedeen fighters and suicide bombers, or of collecting money to finance Al Qaeda-linked groups abroad.