A rescue operation has been launched after a boat with up to 500 migrants on board got into difficulty southwest of Crete.
The Greek coast guard said that passengers on the boat had a made a distress call after drifting into rough seas just after midnight on Monday.
A Greek navy frigate, two Italian fishing vessels, a tanker and two cargo ships were participating in the rescue operation.
However, strong winds and rough seas meant it had not been possible to transfer any of the passengers from the stricken vessel by the morning, the coast guard said.
"The distress call said there are 400-500 people on board," a coastguard spokeswoman said, adding that the operation was hampered by near gale-force winds.
"They can see the boat, it’s adrift, there is a large number of people on board," she added.
It was not immediately known where the boat carrying the migrants had set sail from, what its intended destination was or what the nationalities of those on board were.
Because of bolstered patrols by the Greek coastguard and EU border agency Frontex in the Aegean Sea, migrant smugglers are increasingly employing the longer and more perilous route south of Crete, Greek officials say.
"Eighty percent of flows from Turkey go straight to Italy," Migration Minister Notis Mitarachi told Skai TV last week.
Tens of thousands of people fleeing conflict and poverty in the Middle East, Asia and Africa try to make their way into the European Union each year via perilous sea journeys, with most attempting to reach Greece from neighbouring Turkey or taking a longer route to Italy.
