November 17, 1998 – The Battle of Yosu, in December 1998, was a naval skirmish that began when the Republic of Korea Navy intercepted a North Korean semi-submersible vessel attempting to land commandos on the southern South Korean coast. Throughout 1998 there had been several incidents involving North Korean infiltrators attempting to land on along the South Korean coastline. In the June 1998 Sokcho submarine incident a North Korean submarine was found in South Korean waters off Sokcho entangled in fishing nets, the submarine was towed to a ROK Navy base and when opened the crew were all dead in an apparent murder-suicide. Another infiltration occurred in July when a dead commando and abandoned infiltration craft was discovered near the city of Donghae. On December 17, a ten ton North Korean I-SILC class semi-submersible infiltration vessel was observed by a South Korean guard post about 2km off the coast of Yeosu and ROK Navy ships were scrambled to intercept it. After several warnings were given, the ROK Navy fired warning shots at the semi-submersible. The North Korean craft ignored the warnings and opened fire on the South Korean vessels. It then attempted to escape, fleeing southwest while being tracked by patrol planes and boats, but several hours later it had sunk in 300 feet (91 m) of water approximately 100km south of Geojedo. The ROK Navy attempted to recover the bodies of the dead North Koreans and pieces of the infiltration craft. The body of one North Korean frogman was found. From the size and type of the vessel it was assumed that the entire crew consisted of four sailors and that all had perished. Searches were also conducted on nearby land to make sure that infiltrators had not landed on the coastline. When questioned, the North Korean government denied sending the vessel or knowing anything about its origins. This incident helped fuel increasing tensions between the two governments and an even larger naval skirmish was fought the next year.