Greece's coastguard said Monday at least six people have died including a young boy in a suspected migrant boat sinking off the island of Lesbos.
"A Greek navy vessel found five bodies off the island of Lesbos," a coastguard spokeswoman told AFP.
"One more body was found later. So far the bodies of a man, four women and a boy have been recovered," she added.
A pregnant woman was also found in the same area and was taken to hospital, the coastguard said.
No information was immediately available on the nature or size of the vessel that the suspected migrants were boarding.
Greek authorities had received no distress call prior to finding the bodies, the coastguard spokeswoman said.
Several vessels are continuing the search.
Weather conditions in the area are mild.
Greece's Aegean Sea islands are a primary transit point for refugees and migrants seeking to reach Europe from Turkey.
Over a million people have landed in Greece since 2015, most of them fleeing civil war in Syria.