Eight people died, including a child, and five others were missing on Wednesday after a boat carrying migrants towards Greece capsized off western Turkey, local media reported.
The nationalities of those onboard were not immediately known but media reports said they were believed to be Syrians.
Three people were rescued and taken to a nearby hospital after the accident off the Turkish western city of Izmir, the Cihan news agency said.
Turkey, which according to the government hosts about 900,000 Syrians who have fled the civil war in their country, has become a hub for migrants seeking access to Europe.
Neighbouring Greece is the busiest entry point for migrants into the European Union.
But the journey across the Mediterranean is frequently perilous, and hundreds of migrants drown en route each year.