1998 Yeosu submersible incident

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 South Korean navy base and sunk while in tow. When recovered from 30m of water and 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.[1]

On December 17, 1998, a ten-ton North Korean I-SILC-class semi-submersible infiltration vessel was observed by a South Korean guard post about 2 km 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 100 km south of Geoje Island.[2][3]

The South Korean 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 died. 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.

The North Korean regime's Korean Central News Agency issued a statement on December 19, 1998:

The South Korean puppets said that they located a "submarine" in the sea off Ryosu, South Jolla Province, at 11:15 p.m. on December 17 and had a battle in which the "submarine" was sunken and they brought a dead body clad in diving-suit to the land. They also said that they issued an order called "Jindogae nN.1" throughout the coastal areas of South Korea and have been put on the red alert. This time, too, the puppets described the "incident" as the "intrusion by the north," shifting the blame on to the north. This frantic anti-communist campaign is a continuation of the anti-communist, anti-north campaign such as the fiction of the "intrusion of the north's vessel" near the coast of the Kanghwa island on the West Sea of Korea and the description of a flock of birds as "something mysterious" in the sea off the Kanghwa island. The incidents have nothing to do with the north. Now the South Korean are trying hard to find a pretext for unleashing a war against the north in line with the U.S. imperialists' moves for war against the DPRK. It goes without saying that the "north's submarine infiltration incident" is a farce cooked up for that purpose. We can no longer remain a passive onlooker to the South Korean continuous anti-communist campaign and slander against the north. The campaign can convince no one. We will take resolute measures so that the provokers may drink a bitter cup. We seriously warn the South Korean not to act rashly.

• 1996 Gangneung submarine infiltration incident
• 1998 Sokcho submarine incident