At least six children drowned on Friday in two separate incidents when their boats sank off Turkey while trying to make the risky crossing to Greece, state media reported.
A first boat loaded with 55 Syrian and Afghan migrants sank in strong winds and high waves in the Aegean after setting out from near the town of Ayvacik for the Greek island of Lesbos, the Anatolia news agency reported.
Turkish coastguards have so far recovered bodies of four Afghan children, it said.
Another two children perished when their vessel heading for the Greek island of Kos sank off the coast near the southwestern resort of Bodrum, Anatolia said.
The boat capsized because of heavy rains and stormy weather, it added.
Turkey, which is hosting 2.2 million refugees from the conflict in neighbouring Syria, has become the main transit point for people fleeing war and misery for a better life in Europe.
Turkey and the European Union have agreed in principle to a refugee action plan, which is expected to be finalised at a summit on Sunday.
The EU is planning to give Turkey cash help as well as provide visa-free travel for Turkish nationals in return for Ankara's help to contain refugee crisis.