Greek authorities say at least 10 people have drowned and two more are missing after a boat carrying about 25 migrants sank in the eastern Aegean Sea.

The coast guard says the fatalities include five children, four men and a woman. Thirteen people were rescued, and a search is underway to locate the two missing. All are believed to have set off from nearby Turkey.

The accident occurred early Wednesday off the small island of Farmakonissi.

At least 820,000 refugees and economic migrants have reached Greece’s eastern islands this year, risking the dangerous sea crossing in frail boats provided by Turkish smuggling gangs. Nearly all have continued north, hoping for a better life in wealthier European countries.

Hundreds have drowned or are missing.