MOSCOW, October 24 (RIA Novosti) - Russian sailors missing in the West Pacific after their cargo ship sank 80 nautical miles off South Korea, could be swept to North Korea's east coast by a northwesterly current, a senior coast guard officer in Seoul said Tuesday.

Twelve of the 18 members of the Sinegorye crew remain missing, with one sailor found dead earlier Tuesday and five survivors hospitalized in South Korea.

"A search-and-rescue operation is covering about 100 nautical miles," the spokesman said by phone. "But a northwesterly current could drift the sailors and the ship's wreckage to the North Korean coast."

The Russian Foreign Ministry said Tuesday it has instructed its Pyongyang embassy to make every effort jointly with local authorities to locate and rescue the remaining crewmembers.

The Sinegorye, which was sailing in the Sea of Japan off South Korea's east coast, sent out an SOS at 1:40 p.m. local time (6:40 a.m. Moscow time/2.40 a.m. GMT) Monday, before communications were lost.

The rescue operation involves South Korean patrol boats, an airplane and a helicopter. The Russian ship Yury Orlenko has sailed from Vladivostok to join the rescue effort, and an Emergencies Ministry Be-200 amphibious plane from the city of Khabarovsk, in Russia's Far East, will arrive at the scene as soon as weather permits, according to Russian officials.

Turbulent weather conditions complicated the rescue operation over the last 24 hours, with a wind speed of 20 meters per second (45 mph) and wave height of around seven meters (23 feet).

However, the storm is gradually easing, with wind speed down to 8-10 meters per second (18-22 mph) and wave height down to 2-3 meters (10 feet), the spokesman said.

The vessel, which was transporting timber, sank within an hour in a sudden heavy storm, which caused the vessel to lurch violently. Most of the timber broke through the holds, damaging hatches and equipment, and water began to flood the ship, one of the survivors said.

The South Korean Coast Guard said survivors will be able to return to Russia as soon as possible, but not less than in two days, once incident-related formalities are concluded.