Up to 70 people trying to reach Europe illegally from Libya have perished at sea in horrific conditions.
Most of the migrants were Somalis
Men, women and children died of hunger and thirst after the boat broke down and drifted for at least 10 days before being spotted by an Italian ship.
Only 15 were alive when rescuers reached the corpse-strewn boat.
Italy has demanded action on both sides of the Mediterranean to tackle traffickers who exploit the desperation of clandestine migrants.
Many of the estimated 85 people who boarded the boat in Libya were Somalis, Italian police said.
They reportedly included seven children, all of whom perished on the way.
The Italian captain who sighted the ship off the southern island of Lampedusa said he found a scene like something out of hell.
The living and the dead were piled one on top of another as survivors had progressively lost the strength to throw the corpses overboard at sea.
"When we came closer to the drifting boat, what we saw was like a vision of hell," said Stefano Valfre, 34.
"The dead were piled up. We approached, but not too close, because we were afraid of upsetting the boat. We threw them some bread and bottles of water to keep them going while they waited for the coastguard."
Of the emaciated survivors, seven were put in intensive care in hospital in Sicily.
The deaths are the latest in a long series of disasters at sea, although the toll is particularly heavy.
Last week, seven Somali migrants reportedly drowned when their boat capsized off Italy. The captain was arrested and charged with multiple manslaughter.
In another incident, a group of 45 Egyptian illegal migrants who set sail for Italy on Sunday were said to have been rescued after their boat capsized during bad weather at sea near Malta.
Italian Interior Minister Giuseppe Pisanu spoke out on Monday, calling on both African and European states to do more to tackle people-trafficking.
"This tragedy weighs heavily on the conscience of Europe but it also puts in the spotlight African governments who are doing nothing to control this exodus," he told a meeting of EU interior ministers in France.
It was, he said, "up to Europe and Africa to work together intensively so as to regulate migration and combat the organisations that cold-bloodedly exploit clandestine immigrants".