A boat with 46 migrants or refugees has sunk in Greece and the coast guard says it is searching for 26 missing off the eastern Aegean island of Lesbos.

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 there were a total of 46 people on board.

No information is immediately available on their nationalities.

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.