Greek officials said two boats crammed with migrants have capsized off the island of Samos, drowning two people.
The coast guard said it has rescued 36 people, but 30 people are missing after the early Monday accident in the waters where hundreds of other migrants have died this year.
Authorities say they do not yet know the nationalities of the migrants.
Coast guard vessels, a cruise liner and search and rescue helicopters were used in the recovery operation.
Thousands of migrants from Africa, Asia and the Middle East often pack into unsafe boats in attempts to get into the European Union. Fatal accidents are frequent.
Greece, Italy and Malta have repeatedly asked their EU partners to do more to help them handle the large number of migrants.