Coastguards have found the bodies of 13 African immigrants aboard a small boat off southern Italy, and survivors say at least 50 more corpses were dumped at sea.
A spokesman for the Italian coastguards said 15 illegal immigrants, all believed to come from Somalia, survived a 20-day odyssey in the Mediterranean Sea.
Survivors told their rescuers that at least 80 Africans had boarded the boat in Libya and that most of them had died at sea.
Coastguards had boarded the battered boat on Sunday evening in international waters south of the tiny Italian island of Lampedusa.
Bodies were stuffed inside the engine room and under the deck. Survivors, some too weak to stand, begged for help and were whisked to Lampedusa aboard a coastguard launch.
"Cold and hunger was the reason for the deaths, according to the survivors," said the coastguard spokesman.
It normally takes just a couple of days to sail from Libya to Lampedusa, and it was not immediately clear why they had spent so long at sea.
The stricken boat was towed to port with all the remaining corpses aboard. Once they docked shortly after dawn, rescuers realised that a woman thought to be dead was still alive. She and five other immigrants were later flown to a hospital in Sicily.
Interior Minister Mr Giuseppe Pisanu called it a "human tragedy that weighed, above all, on Europe's civil conscience". He also called on African states to do more to halt desperate migrants leaving their countries in search of a better life in the West.