At least eight migrants died early Friday after their boat sank off a western Greek island in the Ionian Sea, port authorities said.

Fifteen migrants managed to escape alive and alerted the authorities to the accident near the island of Lefkada, a spokeswoman for the port police told AFP.

"A search is underway for other victims," she said, adding that the migrants were travelling in an eight-metre (26-foot) inflatable dinghy that was found in the area.

Their nationalities and port of departure were not immediately known.

Greece is one of the main ports of entry into the European Union for migrants and refugees fleeing war-torn and impoverished countries in Africa, the Middle East and the Indian subcontinent.

Refugee traffic has soared over the past year, because of stricter controls on the Greek-Turkish northern land border and the ongoing war in Syria.

Europe's immigration policies have come under the spotlight after more than 400 asylum seekers drowned in October in two tragedies near another popular migrant port of entry, the Italian island of Lampedusa.