Some of the thirteen suicide bombers who killed 28 people and injuring around 100 in attacks in Casablanca on Friday may have had links to a local radical Islamist group, Moroccan Justice Minister Mohamed Bouzoubaa said on Sunday.

The assassins came from abroad, though they were Moroccan citizens, Bouzoubaa reportedly told the state television channel RTM.

A fourteenth assailant, who had been injured in the bombings, was being held in police custody on Sunday.

"He gave information on his criminal accomplices and helped identify those who were involved in the operation, the justice minister said, adding that the authorities believe that a little-known Islamist group called Assirat al Moustaquim may have carried out the attacks.

Moroccan police questioned 33 suspects on Saturday.

The four car bombs and explosives strapped to an assassin's body went off at around 10:00 p.m. local time (2200 GMT) in the center of Morocco's biggest city.

At least one suicide bomber detonated explosives attached to his body in a Spanish restaurant. A Spanish cultural center, a Jewish community center and cemetery, the Belgian consulate and a luxury hotel were damaged in the blasts in the restaurant and by the four car bombs.

Mainly Moroccans killed

Although the targets were mainly western, the victims were mostly Moroccan. Seven foreigners were killed in the attacks, three Spaniards, three French nationals and an Italian.

Two policemen guarding the Belgian consulate were also killed and a security guard was injured in the blast there, which damaged the building badly.

Moroccan journalist Aboubakr Jamai told the BBC on Saturday that the targets had likely been chosen because they were not heavily guarded, contrary to American sites in the country.

Al Qaeda suspected

No group claimed responsibility for the bombings, which were the first terrorist attacks to take place in Morocco in recent years.

Initially the Moroccan authorities suspected the al Qaeda terror network -- which is considered responsible for the terrorist attacks in New York and Washington on Sept. 11, 2001 -- of carrying out the bombings.

Experts believe the group was also responsible for the attacks several days ago in Saudi Arabia's capital Riyadh, where 34 people were killed in a neighborhood mainly inhabited by western foreigners.

"The criminals and their backers must be found and tried," German Foreign Minister Fischer said of the bombings on Saturday. The terrorist attacks were a reminder "that the international community must not ease up in its efforts in the war against international terrorism."

Compiled by DW-WORLD staff with material from news agencies.