ANKARA, Turkey (AP) — A cargo ship sank in rough waters off Turkey’s Black Sea coast on Monday, killing six crew members including its captain, officials and media reports said. Seven other crew members were rescued.

Turkish authorities launched a search and rescue mission off the Black Sea coastal province of Samsun after receiving a distress signal from the Panama-flagged vessel, Volgo Balt 214, the governor’s office said.

Samsun Gov. Osman Kaymak told reporters after visiting the survivors in hospital that six crew members, including the captain, died before rescuers could reach the area. He quoted one of the survivors as saying that the hull split into two after being hit by a powerful wave.

The vessel, which was carrying coal, was heading to Samsun from the Russian port of Azov, the coast guard said. It was located about 80 nautical miles (92 statute miles) from Samsun when it sent a distress signal at 8:10 a.m. (0510 GMT; 12:10 a.m. EST).

The crew included 11 Ukrainians and two Azerbaijan nationals, Kaymak said.

The Turkish Coast Guard said a plane, three helicopters and two boats took part in the rescue operation.