A picture released by North Korea's official Korean Central News Agency via KNS shows Kim Jong Un (centre) at Monday's security meeting at an undisclosed location

North Korean leader Kim Jong Un convened a top national security meeting to direct a plan of "immediate military action" in a dispute with the South over drone flights, state media reported Tuesday.

The nuclear-armed North has accused Seoul of flying drones over its capital to drop anti-regime propaganda leaflets, with Pyongyang ordering troops on its border to be prepared to fire, and South Korea saying Monday it was "fully ready" to respond.