At least 22 immigrants have drowned after two boats capsized trying to smuggle them illegally into Greece.
Bodies are still being recovered from the ocean but at least four children are known to have died, including one infant found in its mother’s arms.
The vessels overturned before dawn on Monday in the Aegean Sea off the coast of Samos, near the Turkish border.
The yacht and a dinghy were overloaded but it was not immediately clear what caused them to capsize.
It was the third fatal migrant boat disaster this year.
The Greek coast guard said 36 people - 32 men, three women and a child - were rescued, and a man and child were airlifted to hospital on the mainland.
The survivors were identified as 23 Somalis, nine Syrians and three Eritreans, the coast guard said. The background of those who died was unknown.
Officials recovered the bodies of two women, a man and a boy from the sea, and later found a further 18 bodies - including three children - inside the yacht after it was lifted out of the water.
Survivors told the coast guard between 60 and 65 people had been on the 30-ft yacht and the six-foot dinghy that had set off from Turkey.
“We can't give a precise number of missing people with any certainty,” said spokesman Nikos Lagadianos.
Search vessels, fishing boats and two helicopters were combing the area for survivors or bodies.
A nearby cruise ship helped for several hours before being cleared to continue its journey.
Despite the financial crisis that brought Greece to the brink of bankruptcy four years ago, the country remains a major entry point for people from poor or war-ravaged parts of Asia and Africa seeking a better life in the European Union.
Fatal accidents are frequent as migrants risk the dangerous sea crossing from Turkey.
Before today's incident, 21 people had drowned in similar incidents since the beginning of 2014 and many more have been rescued from the sea.
Additional reporting by PA