North Korea says its front-line army units are ready to launch strikes on South Korea after accusing its rival of flying drones over the capital Pyongyang.

North Korea threatened a “horrible disaster” over the alleged flight of South Korean drones over its capital. South Korea responded sharply, according to Yonhap News Agency. North Korea claimed recently that South Korean drones had allegedly been spotted over Pyongyang three times in a month.

North Korea on Friday accused South Korea of flying drones to drop propaganda leaflets over Pyongyang and threatened to respond with force if a similar incident happened again.