A Mongolian-flagged cargo ship sank off the coast of South Korea's southern city of Yeosu on Friday, killing two of 16 North Korean crew members on board and leaving 11 missing, the Coast Guard and Seoul's unification ministry said.

The 4,300-ton Grand Fortune 1 ran aground at around 1:19 a.m., some 74 kilometers off the coast of Yeosu, South Jeolla Province, after sending a rescue signal, according to officers.

Of the 16 crew members aboard the ship, all North Koreans, two were found dead and three were rescued and rushed to a hospital on the southern island of Jeju, the officers said, adding that operations were under way to find the other 11 missing sailors.

The vessel, carrying some 50 tons of heavy oil and 6,500 tons of steel products, was en route to China from the North Korean city of Chongjin, they added.

The cause of the accident has yet to be identified, though a high seas watch had been in effect at that time, according to the Coast Guard.

"The boat began to leak suddenly and listed to the right side. The load seemed to slide to one side for unknown reasons," a survivor told the officers. "Upon listening to screams, I put on the rescue equipment and escaped from the ship."

The accident took place in international waters some 43 kilometers away from South Korean waters, according to officials, adding that the route is frequented by North Korean vessels.

A Seoul government official, meanwhile, said the government is reviewing an option of returning the surviving North Korean crew members and the bodies of the dead through the truce village of Panmunjom.

"Discussions are under way among ministries concerned about how to repatriate them. We've yet to make a decision, but are mulling contacting the North via the Red Cross channel and sending them via Panmunjom," he said, requesting anonymity.

Asked what will be done if the North Koreans want to defect, the official simply said, "I think they want to return home as it was just an accident. The South Korean authorities have striven to rescue the missing sailors on humanitarian grounds." (Yonhap)