Four young migrants were reportedly missing on Saturday, after their inflatable dinghy overturned north of the Aegean island of Samos.
According to reports, a Greek coast guard vessel located and rescued 25 migrants and refugees who informed authorities that the four children were missing.
A Super Puma helicopter and three coast guard ships were taking part in the rescue operation over the weekend.
In a separate incident, another search operation was under way Saturday to locate a 20-year-old migrant who went missing when a boat carrying 33 migrants and refugees overturned in the sea east of the island of Lesvos.
Thirty-two of the people were picked up by a Frontex vessel. Interim Prime Minister Vassiliki Thanou was expected to visit Lesvos on Sunday to inspect a migrant and refugee reception center and hold a round of meetings with local authorities and officials from Greek and foreign nongovernmental organizations, a day after meeting with Ecumenical Patriarch Vartholomaios on Chios.
Meanwhile, 2,493 refugees and migrants arrived at the port of Piraeus from Mytilene early Saturday aboard passenger ferry Eleftherios Venizelos.