One sailor is dead and seven others are missing after their cargo ship sank in the Black Sea off the Turkish coast, the governor of Istanbul said.

Authorities sent a fast rescue boat, four tugboats and a helicopter to the site of the sinking and were able to save four sailors and recover one body, Huseyin Avni Mutlu told the Anadolu news agency.

The Russian cargo ship Volgo-Balt 199, flying the flag of St. Kitts and Nevis, fell out of communication at 0820 GMT Tuesday before sinking in a heavy story off the coast of Sile, 70 kilometers (43 miles) from Istanbul.

On board the ship, which was carrying coal, were 11 Ukrainian sailors and one Russian.

Elsewhere, a German-owned cargo ship is adrift with 14 sailors on board near Kilyos, in the extreme northern part of the Bosporus, not far from where the other vessel sank, the NTV network reported.

The ship is fighting against heavy seas and winds up to 80 kph (50 mph) and has dropped two anchors to try and avoid running aground.

Salih Orakci, the head of Maritime Security for Istanbul, told NTV that the ship had requested the help of a tug, but the latter was not able to assist the vessel.

"What we'll do is save the crew," Orakci said. EFE