A migrant woman and two children drowned on Wednesday when a boat carrying about two dozen people capsized off the Greek island of Lesbos, the Greek coast guard said.
The coast guard said a helicopter of the EU border control agency Frontex spotted the overturned boat and local divers helped recover the bodies of a woman, girl and baby. It could not confirm their nationalities.
Twenty-one others on board had been rescued earlier on Wednesday by the Turkish coast guard. The circumstances of the accident were not immediately clear.
Some 3,000 people have died trying to cross the Mediterranean this year, the U.N. refugee agency says. Authorities and relief agencies on Lesbos say the island is running out of space to bury the dead.
Thousands of people continue to arrive every day from Turkey, just 4.4 km (2.7 miles) away. The island's beaches are strewn with orange life vests.
Frontex says over 710,000 irregular migrants have entered the EU this year.
The EU has struggled to reach a comprehensive solution to its biggest migrant crisis since World War II. Prime Minister Alexis Tsipras and German Chancellor Angela Merkel discussed the issue on the phone on Wednesday, Tsipras's office said, ahead of an EU summit in Brussels on Thursday.