Palermo police say Muslims who were among migrants trying to get from Libya to Italy in a boat this week threw 12 fellow passengers overboard -- killing them -- because the 12 were Christians.

Fifteen people have been arrested on suspicion of murdering the Christians at sea.

The original group of 105 people left Libya earlier this week in a rubber boat.

Sometime during the trip north across the Mediterranean Sea, the alleged assailants -- Muslims from the Ivory Coast, Mali and Senegal -- threw the 12 overboard.

The boat was intercepted by an Italian navy vessel, which transferred the passengers to a Panamanian-flagged ship.

The arrests were made when the ship docked.