Rescue teams desperately sought survivors on Sunday after two boats carrying migrants sank off the Italian island of Lampedusa.

In the immediate aftermath of the vessels’ loss on Saturday, Italy’s coastguard said it had rescued 57 people and recovered two bodies – those of a woman from Ivory Coast and her 1-year-old child.

Local media reported on Sunday that at least 30 people remained unaccounted for and were feared dead.

Italy’s Ansa news agency said survivors described how the two boats carrying people trying to illegally enter the European Union had set off from the Tunisian port of Sfax on Saturday. One boat was thought to have had 48 people on board and the other 42. Most were reportedly from sub-Saharan Africa.

Reuters said the coastguard plucked the survivors from the water about 46 kilometers southwest of Lampedusa, which is about halfway between the North African nation of Tunisia and the larger Italian island of Sicily. The island has become a major destination for migrants from Africa wanting to enter the EU and claim asylum.

Italy’s interior ministry said 92,000 people have arrived in Italy irregularly by sea so far this year to apply for asylum in the EU. During the same period last year, 42,600 made the perilous journey.

The ministry said at least 2,000 migrants have turned up on the island of Lampedusa in the past few days alone. Most had been rescued by the coastguard and by various charities from small boats in the Mediterranean Sea.

The International Organization for Migration, or IOM, which is the United Nations’ migration agency, said on Sunday both boats that sank on Saturday had been hit by major storms.

Flavio Di Giacomo, a spokesman for the IOM, told the Agence France-Presse news agency an investigation had been launched into the circumstances surrounding the loss of the boats. He said the probe will be conducted from the town of Agrigento, on the island of Sicily.

“Whoever allowed them, or forced them, to leave with this sea is an unscrupulous criminal lunatic,” he said. “Rough seas are forecast for the next few days. Let’s hope they stop. It’s sending them to slaughter with this sea.”

Emanuele Ricifari, the chief of police in Agrigento, said the people-traffickers would surely have known rough seas were expected.

Europe has seen a sharp rise in recent years in the number of people attempting to cross its borders and claim asylum, with the 1.3 million who did so in 2015 the largest influx seen since the end of World War II, 70 years earlier. Many migrants have sought refuge from conflicts in Syria and turbulence in Afghanistan while others have left nations including Nigeria, Pakistan, and Iraq.