File picture handout released 9 Mar 2007 by the Moroccan Press Agency (MAP) shows Saad Houssaini

Moroccan officials say police have arrested an alleged leader of a terrorist group that they believe was involved in the bombing attacks in Casablanca in 2003, and in Madrid, Spain, the following year.

The officials identified the detainee as Saad Houssaini, who is linked to the Moroccan Islamic Combatant Group, known by its French acronym GICM.

They say Houssaini was arrested in Casablanca late Thursday, and is being questioned but has not been personally linked to the bombings.

The bombings in Casablanca killed 45 people, including at least 12 suicide bombers.

In Madrid, Muslim extremists from north Africa blew up four commuter trains, Killing 191 people and injuring about 1,500 others.

Police say they have been looking for Houssaini as part of Rabat's role in the global fight against terrorism.

Moroccan authorities fear that Islamic fundamentalist violence may spill across the border from Algeria, where a militant group recently renamed itself as Al-Qaida Organization in the Islamic Maghreb with the aim of joining similar groups in the region.

Some information for this report was provided by AP and Reuters.