Ten seafarers have been reported missing after the Turkey-flagged general cargo ship Bilal Bal sank some seven nautical miles off the coast of Istanbul.

A search and rescue operation for the missing crew members is currently underway, according to the Turkish Coast Guard.

The 1974-built vessel sank shortly after it sent out a distress signal in the morning hours of November 1 while it was in the Black Sea. The cause of the sinking is still unknown.

The coast guard deployed three vessels, one helicopter and a plane for the mission.

At the time of the incident, the 2,999 dwt vessel was carrying a cargo of cast iron from the country’s Bursa province to Zonguldak, Reuters cited local media.