The bodies of 12 migrants were found Monday off the coast of Turkey after their boat sank, the Turkish coast guard said. Their boat sank off the city of Bodrum in southernwestern Turkey.
Another 31 migrants were rescued, according to the same source.
At 0720 (0420 GMT), the authorities reported the ship sinking a few kilometers from the Greek island of Kos. The nationality of the immigrants was not immediately clear.
The preliminary toll cited the deaths of eight migrants.
Turkey, which hosts some 4 million migrants and mostly Syrian refugees, is an important transit country for migrants fleeing conflicts in the Middle East and seeking to reach Europe, the bulk of them through Greece.
The migration agreement signed in March 2016 between Turkey and the European Union significantly reduced the movement of migrants from the Aegean Sea to the five islands of Greece closest to Turkey.
In 2015, more than 875,000 immigrants arrived in the Greek islands, according to Ewa Moncourt, a spokeswoman for the European frontier agency Frontex.
But the figure has fallen to less than 40,000 a year in 2017 and 2018.
Between January and June of this year, 555 migrants were killed as they tried to cross the Mediterranean, according to the International Organization for Migration (IOM).
A total of 924 people were killed in this risky trip last year, with the highest figure in 2016 killing 2911 people.
