A dozen migrants believed to be from Syria and Afghanistan — including four children and a baby — drowned Saturday off Turkey while trying to reach the Greek island of Lesbos, authorities said.

The Turkish coast guard told Reuters that 23 people were rescued near the town of Ayvacik, a few miles from Lesbos.

“The coast guard made an announcement saying a boat carrying Syrian migrants had sunk . . . and we went to the area to help them,” said fisherman Sezer Simsek, who helped rescue four people. “We pulled out six bodies.”

Thousands of refugees — mostly from Syria, Afghanistan and Iraq — try to cross the often-rough Aegean Sea daily from Turkey.

So far this year, almost 400,000 people have arrived in Greece, according to the Office of the UN High Commissioner for Refugees.

European Union leaders have agreed to offer Turkey funds, easier visa terms and renewed consideration of its EU membership bid in an effort to secure cooperation on encouraging refugees not to head to Europe.

Meanwhile, hundreds of migrants arrived in Slovenia on Saturday via a new route after Hungary closed its border with Croatia.

About 140,000 have passed through the now-closed border since mid-September.