North Korea on Saturday accused South Korea’s military of firing more than 10 warning shots at its soldiers near the heavily fortified border, calling the action a “serious provocation” that could push inter-Korean tensions to an uncontrollable level, according to a statement carried by the state-run Korean Central News Agency. Ko Jong-chol, vice chief of the Korean People’s Army General Staff, said the incident occurred on 19 Aug. when North Korean troops were building a permanent barrier close to the Military Demarcation Line. He claimed Seoul used a 12.7-millimeter machine gun and warned that Pyongyang would take unspecified countermeasures if its construction activities are hindered again. South Korea’s Joint Chiefs of Staff confirmed firing warning shots after several North Korean soldiers briefly crossed the demarcation line at around 3 p.m. local time that day and retreated. Seoul said the measure was in line with standard rules of engagement and denied any intent to escalate the situation. The exchange came in the middle of the annual Ulchi Freedom Shield drills between South Korea and the United States, which Pyongyang routinely denounces as a rehearsal for invasion. It also follows President Lee Jae-myung’s pledge to scale back some frontline activities in an effort to revive dialogue with the North, even as Pyongyang fortifies the frontier and issues repeated threats of retaliation.