At least 52 people remain missing after a South Korean fishing boat sank off Russia's far-east coast on Monday, with overnight searches not being able to locate any survivors, South Korean officials said. The tragic incident was described as "heartbreaking" by South Korea's Prime Minister Chung Hong-won, BBC News reported.

Four empty lifeboats were recovered and seven people were saved after the ferry Oryong 501 sank in the western Bering Sea off the Chukotka peninsula on Monday, a Russian official said, adding that hopes to find the lost crew members was fading.

"Overnight rescue efforts produced no tangible results and 52 people are still missing," a Sajo Industries spokesman said.

Among the 60 cre members, it was carrying one Russian inspector, 11 South Koreans, 35 Indonesians and 13 Philippine crew members. While the Russian, three Filipinos and three Indonesians were rescued after they used a lifeboat, the Korean sailor was confirmed to be dead.

Although one unidentified dead body was spotted floating in the area, rescuers failed to recover it due to devastating storm conditions, Agence France-Presse quoted a Russian marine rescue official as saying.

"Four torn lifeboats were found," said Oleg Karev of the marine rescue center in the port of Petropavlovsk-Kamchatsky which is participating in the rescue mission.

On Monday, the 36-year-old trawler, which weighed nearly 2,000 tons and was operated by South Korea's Sajo Industries, was fishing for pollock when stormy weather caused seawater to flood a fish storage area, triggering the ship to tilt and eventually sink.

When crew members failed to pump out the water, the ship captain allegedly issued an order to abandon ship, a Sajo official told the Associated Press.

Following the incident, four ships continued to comb the site, but their search was hampered by poor weather conditions and rough seas, the spokesman said.

"We still don't really know how many may have managed to take to the life boats," he said.

Meanwhile, an emergency meeting was convened by South Korea's government officials, with Hong-won stating that they would work with Russia to speed up search efforts.

"The unfortunate accident truly breaks my heart. Above all, I pray the deceased rest in peace and hope that the missing people are quickly rescued," he told reporters.

In April, more than 300 passengers were killed after the Sewol ferry sank, prompting an overhaul of the coast guard and tightening of maritime regulations and ship safety checks.