Greece's coast guard says it is searching for 26 migrants or refugees missing off the coast of the eastern Aegean island of Lesbos after the boat they were travelling in sank.

The coast guard says a Lithuanian helicopter from the European border patrol agency Frontex spotted people in the sea off the southeastern coast of Lesbos early Sunday. Two coast guard vessels headed to the area and have rescued 20 people. The survivors say they were in a boat that sank with a total of 46 people on board.

No information is immediately available on the nationalities of the survivors.

Hundreds of thousands of asylum seekers, mostly Syrians and Afghans fleeing conflict at home, have arrived in Greece from the nearby Turkish coast so far this year.