Nineteen people, including six children, have drowned off the coast of the Turkish city of Izmir after their boat capsized in the Aegean Sea.
Rescue teams managed to save 21 people and were still looking for one other survivor, according to the Turkish coast guard.
The boat capsized near the town of Dikili, which lies directly across from the Greek island of Lesbos.
Thursday's deaths are the third in as many days between Turkey's south-western coast and nearby Greek islands and coincide with falling temperatures and rougher seas.
The Greek coastguard on Wednesday said a small plastic boat carrying migrants from Turkey sank off the small island of Farmakonissi, drowning at least 13, mostly children. Another 11 migrants died on Tuesday in the Aegean.
Earlier this week, the Geneva-based International Organisation for Migrants (IOM) said more than one million asylum-seekers have entered Europe, almost all arriving by sea. It said 3,692 people have drowned trying to get into Europe.
Most people entered Europe via Greece, which took in 820,000 people this year, nearly all of them crossing from Turkey by boat across the Aegean Sea. Of the deaths, the IOM said 706 drowned trying to get to Greece.
In an effort to stem the flow, the European Union, which is facing its biggest refugee crisis since the Second World War, has earmarked billions for Turkey to deal with migrants in its territory.
Turkey, which according to the authorities is hosting 2.5 million Syrian refugees, is a stepping stone for migrants fleeing war and seeking better economic opportunities in the European Union.