A massive search and rescue operation was underway off the Greek island of Folegandros yesterday, after a dinghy carrying migrants sank, killing at least one person, Greek authorities said.

The coastguard said it had rescued 12 people, including children. The body of one dead person was recovered.

But there were conflicting reports about exactly how many people had been on the boat, with some survivors putting the number at 32, while others said as many as 50 were on board, a coastguard official told AFP.

Four coastguard vessels, two navy and air force helicopters, a military transport plane, five nearby ships and three private vessels were all taking part in the search and rescue operation, the coastguard said.

Those rescued -- seven Iraqis, three Syrians and two Egyptians -- were all transferred to the hospital on the island of Santorini.

Nearly one million people, mainly Syrian refugees, arrived in the EU in 2015 after crossing to Greek islands close to Turkey.

The report comes as the International Organization for Migration said on Tuesday said that at least 160 migrants had drowned off Libya's coast after their boats sank over the past week.