The Turkish coast guard rescued 31 migrants whose boat sank in the Aegean Sea.
At least 12 migrants were killed as a boat capsised off the south-western Aegean coast of Turkey on Monday. Another 31 migrants were rescued.
Search and rescue operations for the missing are under way.
At least 50 illegal immigrants lost their lives on their way to Europe through Turkey this year, according to data compiled by Anadolu Agency in May 2019.
Most of the deaths took place along the Turkish-Iranian border, where 32 migrants froze to death while trying to cross to Van province in eastern Turkey from Iran.
In four separate incidents on the Aegean Sea, a total of 16 migrants drowned while trying to cross to Greek islands.
Turkey has been the main route for refugees trying to cross into Europe, especially since the beginning of the civil war in Syria.
Some 268,000 migrants were held in Turkey in 2018, according to the Interior Ministry.
The migrants were mostly Afghan, Pakistani, Syrian and Iraqi nationals.