Eleven Syrians were killed when their inflatable boat sank off the country's Aegean coast, Turkish media reported Friday.
The Dogan news agency said five of the dead were children, and a baby rescued in critical condition was among 11 people who survived the accident.
Television footage showed rescue workers standing next to covered bodies near the Turkish resort town of Kusadasi. Media reports said two Turks, thought to be people-smugglers, had been detained.
The boat capsized in strong wind and waves and was thought to be trying to reach the Greek island of Samos.
The deaths came a year after a European Union-Turkey agreement to curb illegal migration, which has significantly reduced the number of migrants trying to reach the bloc from Turkey.
The U.N. refugee agency said more than 3,620 refugees and migrants had crossed from Turkey to Greece this year, compared with nearly 150,000 arrivals in the equivalent period last year before the agreement was signed.
Under the deal, Turkey agreed to tighten its maritime borders and control immigration in return for aid and accelerated EU membership talks.
Turkey's president, Recep Tayyip Erdogan, has raised alarm in Europe by saying he will review the agreement. Tension between Turkey and the EU has been heightened during a campaign for a Turkish referendum aimed at boosting the president's powers.
In another development, a Spanish aid organization said Friday that it feared hundreds of migrants might have died off Libya's coast. Spain's Proactive Open Arms group said it found five bodies near two capsized boats on Thursday and another body on Friday. The group said it thought there could have been hundreds of people on the two boats.
Libya's coast guard said it had no reports of dead migrants in Libya's waters.