SOFIA, Sept 27, 2008 (AFP) - A Russian boat sank early Saturday off Bulgaria's Black Sea coast, with all crew members still missing, the Bulgarian transportation ministry said.

The boat, under a North Korean flag, did not give a distress signal, but the Bulgarian authorities were alerted by a Russian satellite centre, said Nikolai Apostolov, head of the Bulgarian maritime office.

No information had been received to date about the number of crew on board, he added.