A shipwreck in which about 400, mostly women and children migrants are feared to have died off Libya this week was said to have been caused by excitement at the sight of rescuers.
Monday's sinking is among the worst migrant tragedies in the Mediterranean.Aid agencies say not enough is being done to save the lives of the rising number of people trying to cross the sea to Europe.
Up to 20,000 people fleeing poverty and conflict have made the perilous crossing to Italy since the start of the year, similar to the same period in 2014, a year when a record 170,000 reached the country's shores.
Almost 10,000 people have been picked up in recent days, and more boats are heading for the Italian coast.
The Italian coast guard rescued about 140 people from the boat that capsized on Monday. Survivors say more than 500 people were on board when it sank. (Read story here)
Joel Millman, a spokesman for the International Organization for Migration (IOM) quoted by Reuters news agency, says that at least a third were women and children.
"When the men on the deck became restless and started moving about because a rescue boat was beginning to approach them, the boat capsized and water flooded the hull," he said. "Women and children died immediately."
More than 500 people have died attempting to cross the Mediterranean since the start of the year, 30 times more than in the same period last year.
If the toll from latest tragedy is confirmed, the number of deaths for the year would rise to 900.
The migrants are said to be of Somalia, Eritrea and Syrian nationals.
