Twenty-seven survivors of Sunday's Mediterranean shipwreck arrived on a coast guard vessel at the Italian port of Catania on Monday night.
According to the UN's latest figures, the disaster killed 800 migrants who had embarked on the perilous crossing from Libya, desperate for a better life in Europe.
Italy's infrastructure and transport minister Graziano Delrio said two of the survivors – the captain and his deputy – had been arrested on suspicion of human trafficking.
Meanwhile, off the Greek island of Rhodes, 93 migrants were rescued from a wooden boat that sank after crashing onto rocks. Three died: a man, a woman and a child.
The European Union has proposed doubling the size of its search and rescue effort in the Mediterranean.
Two more rescue operations are still underway to save an estimated 400 migrants in danger off the coasts of Libya.