A major rescue operation is under way after a cargo ship carrying 14 crew members and a load of salt, sank off the coast of Lesbos island in Greece as high-speed winds tilted the vessel causing it to take on water.

The Comoros-flagged ship Raptor, which was travelling from Dekheila, Egypt to Istanbul, sank 4.5 nautical miles (8.3km) southwest of Lesbos early on Sunday.

According to the Greek coastguard, five cargo ships, three coast guard vessels, air force and navy helicopters as well as a navy frigate have joined the rescue effort to search for the crew members, of whom only one has been rescued.

The crew member was airlifted from the sea by a navy helicopter during gale force winds, according to the coastguard and taken to Lisbon General Hospital for treatment.

The ship first reported a mechanical failure at 7am local time (05:00 GMT), but by 8:20am, the captain had sent out a Mayday distress call and reported that the ship was tilting. The ship disappeared from the radar shortly after. Authorities suspect that the heavy load caused the ship to list and sink once it took on water.

The Athens News Agency (ANA), quoting the operating company of the ship based in Lebanon, said that crew members included Syrian, Indian and Egyptian nationals.

‘Dangerous weather phenomena’

Ships remained docked across several parts of Greece over the weekend, with wind speeds reaching 9-10 on the Beaufort scale, meaning a strong gale to storm force. The Beaufort scale which ranges from 0 to 12 estimates wind strength.

An emergency weather warning by the Hellenic National Meteorological Service (EMY) was upgraded on Saturday from “worsening weather” to “dangerous weather phenomena”, as Storm Oliver (also called Bettina) moved from the Adriatic Sea toward Greece.

The country has been struck by repeated flooding over recent months after being hit by a series of storms.