Rome/Paris: A humanitarian group said it recovered the bodies of four migrants and rescued around 400 survivors on Tuesday from an overcrowded wooden boat in the Mediterranean between Italy and Libya.
The dead had suffocated below deck, the Malta-based Migrant Offshore Aid Station (MOAS), whose Topaz Responder rescue ship carried out the operation, said on Twitter.
Emergency, another humanitarian organisation, was treating another person who was found on the same boat in a critical condition, MOAS said.
A spokesman for the Italian coast guard, whom rescuers have to contact when they pick up people at sea, said around 500 people had been saved in three rescue missions on Tuesday, all around 20 miles (32 km) from the coast of Libya.
The coast guard spokesman, who could not confirm the death toll, said the Bourbon Argos, run by humanitarian group Doctors Without Borders, had gone to the rescue of a rubber boat.
A third mission, involving a small boat carrying about 20 people, was still in progress, the spokesman said.
Italy's Navy said in a separate statement that one of its helicopters had air-lifted one migrant in respiratory arrest towards the island of Lampedusa, and that two of its ships had been involved in rescues. It was not clear whether they were the same incidents reported by the coast guard.
Italy has been on the front line of Europe's worst migration crisis since World War Two, which is now in its third year.
More than 67,000 seaborne migrants had arrived in Italy by early July, according to the International Organisation for Migration, and 2,499 had died attempting the crossing.
Meanwhile, the number of illegal migrants entering Europe has fallen since April after the European Union sealed a deal with Turkey to halt flows across the Aegean Sea, the border agency said, and Italy has become the new frontline for refugees, mostly from Libya.
"For the first six months of 2016, there were 360,000 illegal entries in the EU, which is higher than what we saw last year, but the influx has been diminishing since April," Fabrice Leggeri, executive director of Frontex, the agency in charge of protecting the bloc's external borders, told Europe 1 Radio.
Leggeri said Italy had overtaken Greece as the primary point of entry and most migrants were now embarking for Europe in Libya. About 750 were arriving in Italy daily compared with about 50 in Greece.
"So the new frontline is Italy," he said.
In all of 2015, Frontex recorded more than 1.5 million irregular border crossings into Europe, mostly to Greece before marching north to Germany and Sweden, fleeing war and poverty in the Middle East, North Africa and elsewhere.
A Frontex spokesman said the EU-Turkey deal, under which Turkey agreed to halt illegal migration through its territory in return for financial and political rewards, and the closure of the Greece-Macedonia border earlier this year, were the two main reasons behind the declining figures.
Leggeri was speaking ahead of a news conference on plans for the agency's future later on Tuesday.
Most of those arriving in Italy were from sub-Saharan Africa, he said.
A humanitarian group said it had recovered the bodies of four migrants and rescued around 400 survivors on Tuesday from an overcrowded wooden boat in the Mediterranean en route to Italy from Libya. The dead suffocated below deck, the Malta-based Migrant Offshore Aid Station, whose rescue ship carried out the operation, said on Twitter.
The EU is preparing to rename Frontex, based in Warsaw, the European Border and Coast Guard Agency, with a two-fold increase in staff and funding worth 322 million euros by 2020.
Border protection would remain a national responsibility and the agency will continue to rely on EU capitals for contributions to a proposed pool of 1,500 border guards ready for quick deployment to any crisis spot.