Belgian police have arrested a man wanted by Moroccan authorities in connection with homicide attacks that killed 45 people, including 12 bombers, in May in Casablanca, the prosecutors' office said Friday.

The arrest came as police raided about 20 houses in Brussels and two northern towns, the Federal Prosecutors' Office said in a written statement.

Officials declined to name the suspect, but said the man is believed to be linked to a group called the Moroccan Islamic Combatants Group (search), which has been under investigation by Belgian police and intelligence services.

There is "serious evidence" that North Africans linked to that group have received paramilitary training in Afghanistan and are now in Belgium, the statement said.

Spanish police believe there are links between the Casablanca bombers and suspects held for the attacks on trains in Madrid last week that killed 202. However, the Belgian investigation was not directly related to the Madrid attacks, said Lieve Pellens, a spokeswoman for the prosecutors' office.

The raids took place in three Brussels neighborhoods with large North African immigrant populations and in the northern towns of Maaseik and Kapellen, both close to the Dutch border.

The prosecutors' office said there may be a link with another suspect arrested in the Netherlands.

A Spanish judge charged three Moroccans on Friday with mass killings in the Madrid terror attacks and sent them and two Indian suspects to prison pending further investigation. Five other suspects were arrested in Spain on Thursday.

The Casablanca attacks were blamed on Salafia Jihadia (search), a secretive, radical Islamic group believed linked to Al Qaeda. A Muslim cleric wanted in the attacks is currently being held in Italy, while Morocco seeks extradition.

Moroccan authorities have arrested about 1,100 terrorism suspects since the May 16 Casablanca bombings, which targeted a major downtown hotel, a Jewish community center and a Spanish restaurant.

Islamic radical groups with links to Al Qaeda are suspected of setting up networks in Belgium and other European nations with large Muslim communities.

On Sept. 18, Islamic militants were convicted by a Brussels court of involvement in a terror ring that worked around Europe to recruit fighters for Al Qaeda and Afghanistan's former Taliban rulers.

One of those convicted, Tunisian Nizar Trabelsi (search), received a 10-year sentence after admitting he planned to drive a car bomb into a Belgian air base where about 100 American military personnel are stationed.