Sharks attacked migrants who fell from overcrowded boats in the Mediterranean, it is claimed.
The Libyan Navy said 31 people were dead and another 40 missing when it arrived at the scene of two upturned boats that were headed for Europe.
Many of the bodies had bite marks from deadly blue sharks, with some of the killer fish spotted nearby, the navy said on its Facebook page.Three children and 18 women were among the dead.
It described how terrified survivors were found scurrying to get on top of the upturned hulls away from the sharks.
The post read: “We found dozens of bodies floating in the water and two small boats with hundreds of people crowded on board and others holding on or trying to climb aboard to escape from the sharks.”
One sailor told Italian newspaper Il Giorno: “There were lots of bodies all around and we saw there were four or five sharks swimming among them, large blue sharks, a very aggressive species.
“When we brought the bodies on board, we noticed that some of them had been bitten, so it’s possible that among the missing some may have been eaten.”
The stranded migrants were found 40 miles off the coast of North Africa and were believed to be heading for southern Italy or Malta.
Officials said 200 survived the horrific ordeal.
Around 1,800 people were rescued in the Mediterranean over four days last week.
About 161,000 people had crossed the sea to Europe so far this year and almost 3,000 were known to have died.
Many begin their journeys from lawless Libya, where people traffickers ferry thousands to Sicily, Lampedusa and Malta.