Greek authorities launched a search-and-rescue operation off the island of Lesbos on Monday after rescuing seven illegal immigrants from the sea southwest of Cape Agrilia, officials said.
Two people were also recovered unresponsive, the coast guard said, adding that the search is continuing for any additional missing persons.
The operation involves two vessels, a helicopter, and a land-based coast guard unit, it added.
Greece, at the southern tip of the European Union, has long been a favoured gateway to Europe for illegals from the Middle East, Africa and Asia.
The Mediterranean nation has recently toughened migration rules, following a resurgence of arrivals from Libya via the Greek islands of Crete and Gavdos.
(Reporting by Antonis Pothitos; Editing by Toby Chopra)