Five men have been arrested on suspicion of murder over the deaths of dozens of migrants on an overcrowded ship trying to reach Italy.
The arrested men are accused of stabbing, assaulting and throwing overboard some 60 migrants.
The suspects include two Moroccans, a Syrian, a Saudi Arabian and a Palestinian.
Authorities rescued more than 550 people on the ship over the weekend after it got into trouble as it tried to sail from Libya to Sicily.
At least 140 migrants died during the ill-fated crossing.
It is alleged a fight broke out over whether to return to Libya and over the conditions on the ship.