Survivor accounts of the number aboard varied, with the Italian Coast Guard saying that the capsized boat had a capacity for "hundreds" of people.
Italian prosecutors said a Bangladeshi survivor flown to Sicily for treatment told them 950 people were aboard, including hundreds who had been locked in the hold by smugglers. Earlier, authorities said a survivor told them 700 migrants were on board.
Eighteen ships joined the rescue effort, but only 28 survivors and 24 bodies had been pulled from the water by nightfall, Renzi said yesterday.
These small numbers make more sense if hundreds of people were locked in the hold, because with so much weight down below, "surely the boat would have sunk," said Gen Antonino Iraso, of the Italian Border Police, which has deployed boats in the operation.
The man said about 300 people were in the hold, locked in there by the smugglers, when the vessel set out. He said that of the 950 who set out aboard the doomed boat, some 200 were women and several dozen were children.
Iraso said the sea in the area is too deep for divers, suggesting that the final toll may never be known. The sea off Libya runs as deep as 3 miles (5 kilometers) or more.
So far this year, 35,000 asylum seekers and migrants have reached Europe and more than 900 are known to have died trying.
