Greece's coastguard said it was engaged in two separate rescue operations on Tuesday in search of dozens of migrants missing after their boats coming from Turkey overturned in gale-force winds.
A coastguard spokesperson said nearly 60 people were believed to be missing near the island of Evia after their vessel sank in winds of over 60 kilometres per hour.
Nine men had been found and rescued from a rocky islet in the Kafirea Straits between Evia and Andros.
The survivors estimated 68 people had been on board the sailing boat that left from Izmir, on the Turkish coast, headed to Greece.
Passengers had alerted authorities on Tuesday morning, saying they were in trouble. But they did not provide a location.
The coast guard said a helicopter, a coast guard patrol boat and two nearby sailing ships were participating in the search and rescue operation under gale-force winds.
A separate rescue operation has been ongoing since Monday off the coast of the Aegean island of Samos after eight people were reported missing from an inflatable dinghy that overturned.
The four migrants rescued from the craft said there had been 12 people on board.
Greece saw an influx of about a million refugees in 2015 and 2016, as people fleeing war and poverty in Syria, Iraq and Afghanistan arrived from Turkey.
The number has since fallen, but authorities said they had recently seen an increase in attempted entries through the islands and Turkish land border.
The coastguard had said it rescued about 1,500 people in the first eight months of this year, compared to fewer than 600 last year.
(with wires)
