Police in the Sicilian capital Palermo said on Thursday they had arrested 15 Muslim men from the Ivory Coast, Mali and Senegal on charges of throwing the group of Christians from a migrant boat in the Mediterranean. All the Christians are believed to have drowned.

"The motive for the resentment was traced to their faiths," police said. "Twelve people are said to have drowned in the waters of the Mediterranean, all of them Nigerian and Ghanaian."

The 15 were charged with multiple homicide motivated by religious hatred. The International Organization for Migration (IOM) said in a statement that it had received reports of "a fight between different groups - maybe for religious reasons..."

Survivors said they had boarded the rubber boat on April 14 on the Libyan coast with 105 passengers aboard. They arrived in Palermo on Wednesday morning after being rescued at sea by the ship Ellensborg.

During the crossing, the migrants from Nigeria and Ghana - believed to be Christians - were threatened with being abandoned at sea by the group of fifteen. They carried out their threat, according to the witnesses, and pushed the Christians overboard.

The surviving Christians, according to the police statement, only managed to stay on board by forming a "human chain" to resist the assault.

The IOM said some 10,000 people had been rescued off Italy in the last few days. Recent good weather has prompted an increase in the number of boat migrants attempting the dangerous crossing to Italy. Many of them have fled conflict and poverty in Africa and the Middle East.

Italy phased out a dedicated maritime search and rescue operation called "Mare Nostrum" or "Our Sea" late last year, making way for a European Union border control mission.

jm/bw (Reuters, AP)