Sofia (Bulgaria), Sep 27 (Xinhua) A cargo ship Saturday sank in the Black Sea off the coast of Bulgaria and all its crewmembers were reported missing, a media report cited Bulgarian transport ministry as saying.It is still not known how many people were on board the ship ‘Tolstoy’ that sank around 4 a.m. (0100 GMT) off Cape Emine on Bulgaria’s northern Black Sea coast, a spokeswoman for the ministry said.

The ship, with a Korean flag, issued no SOS call (distress call). The authorities only found out about the incident around 11 a.m. (0800 GMT) after a signal was sent from another Black Sea country, she said.

The Bulgarian air force helicopters are currently searching the area for survivors. Military and commercial ships are also participating in the rescue effort.

The bad weather is making the rescue work difficult.