Seoul, 24 October 2022 (dpa/MIA) - South and North Korea early on Monday each fired warning shots along their disputed sea border off the west coast of the Korean peninsula. Seoul's Joint Chiefs of Staff (JCS) said it fired warning shots at a North Korean merchant ship which at around 3:45 am (1845 GMT Sunday) violated the waters of the so-called Northern Limit Line (NLL), news agency Yonhap reported. North Korea then fired artillery shells into the buffer zone in the Yellow Sea. The NLL was drawn unilaterally by a UN command after the 1950-53 Korean War to prevent hostilities between the two sides. It is not recognized by North Korea. The Korean People's Army (KPA) said that a South Korean navy ship "invaded the Military Demarcation Line under the control" of Pyongyang around 3:50 am, opening fire with "the excuse of controlling an unidentified ship." The KPA said that, as an "initial countermeasure," North Korea's coastal defence units fired "10 shells of multiple rocket launchers toward the territorial waters" where movement was detected. "The KPA General Staff once again sends a grave warning to the enemies who made even naval intrusion in the wake of such provocations as the recent artillery firing and loudspeaker broadcasting on the ground front," an English-language statement carried by state news agency KCNA read. The latest incident comes amid high tensions on the Korean peninsula, with an increase in military activity on both sides.