North Korea sent a letter to the United Nations Security Council accusing Seoul of fabricating a landmine explosion that injured three South Korean soldiers, its state media reported Monday. Tensions between the two Koreas have soared since the South last month blamed the blast inside the heavily fortified Demilitarized Zone (DMZ) that separates the countries on landmines laid by the North, an accusation it has fiercely rejected. The North Korean permanent representative to the United Nations sent a letter on Sunday to the UN Security Council regarding the “provocation the ROK committed by groundlessly shifting the blame for the dubious ‘mine explosion incident’”. The letter said that the landmine incident “fabricated by the ROK, is a sinister obstructive move to brand as a ‘military invasion’, delay and impede the DPRK’s fortification of its southern border,” using the acronyms for both countries’ official names. The incident was a “farce to evade the responsibility for the ever-escalating tensions on the Korean peninsula,” it added. It went on to say its ongoing border fortification efforts were “a legitimate and just exercise of its sovereignty going in strict conformity with the UN Charter,” while blasting South Korea for firing warning shots at soldiers involved in the work. “This is a wanton violation of Article 2 (4) of the UN Charter which stresses the need to refrain from the use of force or threat against territorial integrity of any country in international relations,” said the official Korea Central News Agency (KCNA). South Korea’s foreign ministry sent its own letter to the president of the UN Security Council last week, again blaming the explosion on a North Korean landmine and calling it a “clear violation of the armistice agreement”. The statement comes days after South Korea proposed military talks with North Korea to “mutually confirm the precise location” of their border and discuss restoring communication channels. The proposal was announced after Kim Yo Jong, the powerful sister of North Korea’s leader, announced that Pyongyang had moved new troop units into “firing position” along the border.