At least four people were killed while seven others were rescued when a migrant boat sank off the Greek island of Lesbos, the country's coastguard said Monday.
"We recovered four bodies, the rescue operation continues. We don't know if there were more people on the boat," a coastguard official said.
The survivors are Sudanese, local broadcaster ERT said, adding that it was initially unclear how many people were on board the boat.
Strong winds have been sweeping the region, which may have caused the accident and hampered the search and rescue operation, involving several coastguard vessels, a helicopter and search parties on land.
This is the second fatal incident involving migrants off Lesbos, near the Turkish coast, in October.
Greece was on the frontline of a 2015-16 migration crisis when more than a million people fleeing war and poverty in the Middle East and Africa crossed into Europe.
Migrant flows subsequently ebbed. However, the country has toughened migration rules, following a resurgence of arrivals from Libya via the islands of Crete and Gavdos.
According to the United Nations High Commissioner for Refugees (UNHCR), more than 30,000 refugees and migrants have crossed the Mediterranean to Greece so far this year.
