North Korea accused South Korea of flying propaganda-filled drones over Pyongyang and threatened “retaliation,” state media reported Friday.

North Korea has accused rival South Korea of flying drones to its capital to drop anti-North Korean propaganda leaflets and threatened to respond with force if such flights occur again.

South Korea's military said Thursday it is not investigating the alleged flight of South Korean drones over North Korea's capital earlier this month, describing it as a matter to be clarified by the North.