Kim Yo Jong, sister of North Korean leader Kim Jong Un, on Tuesday rejected South Korea’s finding that a North Korean mine likely caused a blast in the Demilitarized Zone and threatened retaliation, state media said.

In the statement, carried by the Korean Central News Agency on Wednesday and titled “The provocateurs must brace for the price of their self-scripted farce,” Kim called the accusation an obvious self-made play that, in its timing and method, she said, closely resembled the “wooden-box mine incident” that stirred tensions more than a decade ago.

The Joint Chiefs of Staff in Seoul had said on Monday that interim findings pointed very strongly to a mine planted by North Korean troops in the Sept. 21 explosion in the western sector of the zone. South Korea’s military has said it will take “corresponding measures” if the mine is finally confirmed as North Korean.

Kim accused the South Korean military of fabricating groundless results and of openly discussing “appropriate and corresponding measures” to manufacture a justification for political and military provocation. Fortification work the North is conducting along the border was “a thorough exercise of sovereignty unrelated to any military purpose,” she said, adding that “our soldiers have never once crossed the border line.”

“If even a single bullet lands on our territory, you must be prepared for much,” she said. If South Korean troops use live fire rather than warning shots against North Korean soldiers, border units “will deliver an immediate and merciless retaliation,” she said, adding that response guidelines had been issued to border defence units and that tactical counterstrike means would be reinforced in the DMZ-facing sector of the South’s 3rd Corps 21st Infantry Division.

The statement did not appear in the Rodong Sinmun newspaper or on domestic state broadcasting, the outlets ordinary North Koreans can access.

In Seoul, the blast continued to divide the parties. Na Kyung-won, a lawmaker of the opposition People Power Party, on Tuesday filed a resolution accusing the government of President Lee Jae-myung of downplaying and concealing what it called a North Korean mine disaster and demanding a full accounting. The opposition had already demanded its own experts join the inquiry.

The resolution demands a fact-finding team that includes opposition-nominated experts in explosives, mines and military investigation; an immediate joint hearing of the National Assembly’s foreign affairs, defence and intelligence committees covering both the blast and the repatriation of North Korean prisoners of war held in Ukraine; and urgent parliamentary questioning on when Lee was briefed, what he ordered and what measures were taken for the wounded.

It calls for personnel and legal accountability for those responsible for the response. If the blast is confirmed as a hostile act involving a mine laid by North Korean troops, the resolution says, the wounded must be classified as combat-wounded and given honours and compensation to match. Soldiers who want to continue serving must be guaranteed a way to do so, while those who choose discharge must receive uninterrupted veterans’ registration, rehabilitation, employment and living support.

“To send soldiers on a dangerous mission, the state must first inform them of the danger; if soldiers are hurt, it must establish the cause to the end; and it must take responsibility for their treatment and their lives afterward,” Na said. “This is not the argument of any faction. It is a basic duty the state owes its soldiers.”

By Tuesday afternoon, the resolution carried the names of People Power Party leader Jang Dong-hyuk, about 50 party lawmakers including Kwon Young-se, Cho Bae-sook, Lee Jong-bae, Ahn Cheol-soo and Park Dae-chul, independent lawmaker Han Dong-hoon and Lee Jun-seok, former leader of the minor Reform Party.

Jin Sung-jun, the ruling Democratic Party lawmaker who chairs the National Assembly’s defence committee, said North Korean intent remained unproven. “Whether it was intentional is something we can only know through investigation. It is difficult to conclude at this point,” he said in a CBS radio interview on Wednesday.

Jin said the case might differ from the 2015 wooden-box mine episode, in which, he said, North Korean soldiers planted mines at a gate used almost daily by South Korean troops conducting searches in the zone, seriously injuring non-commissioned officers. Asked whether the newly found mine could have been defensive, he said: “That is something we can know only after further investigation.” In a radio interview the previous day he had said it was hard to conclude the mines were planted to harm South Korean troops.

Still, Jin said, the confirmation that North Korea laid mines south of the Military Demarcation Line was “a violation of the Armistice Agreement, and broadly speaking, a military provocation.” The strength of any response could vary, he said, adding that if North Korean intent and targeting are established, “we will face a situation in which the level of the response must be raised.”

Seoul answered the 2015 incident by resuming propaganda loudspeaker broadcasts toward the North. The military’s final determination on last week’s blast is pending, and Na’s resolution awaits consideration in the National Assembly.