The South Korean Navy ship fired five warning shots with a 40 mm-caliber gun. The ship retreated to the North 18 minutes after the shots were fired. No damage was seen on the ship, Seoul authorities said.Pyongyang called the South’s use of the gun a “deliberate military provocation,” warning that the inter-Korean relations could return to the point before the two sides struck a comprehensive deal on Aug. 25 to defuse cross-border tensions.The North’s vessel came some 700 meters into the South Korean waters at around 3:30 p.m., according to Seoul authorities. At the time, the vessel was carrying out a stepped-up clampdown on some 100 Chinese vessels operating near the Northern Limit Line, the de facto sea border.“In the process of (the North) making its retreat, there was no naval clash or anything,” said a military official on condition of anonymity. “We are keeping closer tabs on the North Korean military’s movements and strengthening our readiness posture.”The North’s violation of the NLL raised tensions as the two Koreas were holding reunions of families that have been separated since the 1950-53 Korean War at Mount Geumgangsan on the North’s east coast.The North’s Committee for Peaceful Unification of the Fatherland criticized the South, arguing that Seoul carried out a “military provocation” intentionally targeting its naval vessel.“The South Korean military’s warmongers fired a barrage of shots toward our vessel that was conducting a normal maritime mission,” said the committee’s unnamed spokesperson in an interview with the North’s Korean Central News Agency.“It is a deliberate provocation that is intended to raise military tensions again in the West Sea.”Seoul authorities countered that they fired the warning shots in accordance with “due procedures.”“It was not the first time that the North’s patrol ship has violated the NLL,” a Seoul official told reporters on condition of anonymity. “When a North Korean ship crosses the NLL into the South, the Navy is immediately to make a warning announcement and then fire warning shots.”Since the Aug. 25 agreement, the North has violated the NLL twice. On Aug. 31, a North Korean patrol ship retreated to its waters after the South fired three shots with a 40 mm-caliber naval gun. As of October, the North violated the NLL more than 10 times, according to Seoul authorities.The North has often violated the NLL in what Seoul claims to be a move to turn the waters near the NLL into a disputed area.The North contests the NLL as a maritime border, as it was drawn unilaterally by the then U.S.-led U.N. Command after the end of the Korean War. The North argues the NLL should be redrawn further south.By Song Sang-ho ( sshluck@heraldcorp.com