A baby and a toddler were among seven people who died when a boat carrying migrants and refugees sank in the eastern Aegean Sea, the Greek coastguard said.
The boat, which had been travelling from Turkey, capsized on Friday near the small Greek island of Oinousses, about eight kilometres (five miles) from the Turkish coast.
Twelve people were rescued, the coastguard said, before adding four people were missing.
Rescue crews initially recovered the bodies of a baby and a four-year-old child. But after survivors told authorities that four people on the boat were still missing, the bodies of three more children and two women were found.
Patrol vessels and a search-and-rescue aircraft from the European Union's border protection agency Frontex were involved in the effort
The coastguard did not provide details on the nationalities of the victims.
The incident is among the deadliest of its kind in Greek waters this year and comes as the country deals with a resurgence in refugee and migrant flows from neighbouring Turkey.
More than 9,000 people arrived in Greece in August, the highest number in the three years since the EU and Ankara implemented a deal to shut off the Aegean migrant route.
More than 8,000 people have arrived so far in September.
Greece is hosting some 70,000 mostly Syrian refugees and migrants who have fled their countries since 2015 and crossed over from neighbouring Turkey.
Prime Minister Kyriakos Mitsotakis this week said some 3,000 people had arrived from Turkey in recent days, placing additional pressure on camp facilities on Greek islands that are already vastly overcrowded
Hundreds of migrants and refugees have died in recent years while attempting to cross the Aegean Sea in small, overloaded boats.
More than 50 have died so far this year, according to the International Organization for Migration.