Three members of the Togo-flagged Ag-Marina were missing on Thursday after the cargo ship went down in the early hours 30 nautical miles off the western coast of Crete, the Athens-Macedonia News Agency reported.

Four crew members were rescued by coast guard officers and three, possibly Russian nationals, are missing, according to reports.

Four cargo ships, a helicopter and coast guard craft are being used in the search.

There was no information regarding the ship's cargo or the circumstances that led to its sinking.