South Korean activists have angered Pyongyang by firing leaflets across the border at night. Pictured: A barbed-wire fence separating North and South Korea, at Paju, South Korea. Getty Images/Chung Sung-jun

North Korea said Friday it will attack Seoul unless its southern neighbor stops activists from launching propaganda leaflets across the border, according to a report in the Korea Observer, a pro-South Korea news website. The threat comes days after South Korea accused Pyongyang of laying land mines that maimed two soldiers who were walking on a path inside the southern side of the demilitarized zone.

While the North has denied laying the mines, the incidents have added to the deteriorating relations between the neighboring countries. "The puppet forces should not forget even a moment that the whole of South Korea might turn into a sea of fire due to the foolhardy leaflet-scattering operations," the North warned in a statement released through its official Korean Central News Agency (KCNA).

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While South Korean police have attempted to stop the leaflets being fired over the border, the activists have been accused of employing hit-and-run tactics that have involved sending across anti-Pyongyang propaganda more than a dozen times at night during June, July and August.

Kim Jong Un’s dictatorship termed the dispersal of the leaflets an "an open declaration of a war,” according to the statement, which added that South Korea should not test the patience of the North’s soldiers.

After discovering the land mines that were buried all along the heavily fortified border earlier this week, South Korea commenced broadcasting government messages condemning Pyongyang's government from large speakers inside the demilitarized zone. The move will likely infuriate North Korea, which has threatened to destroy the speakers in the past.

Seoul has vowed that the North will pay a “harsh price” for the attacks, while also announcing that it would be conducting a series of live military drills with the U.S. military not far from the border.