The North's planes, including fighters and bombers, were spotted flying between around 11 a.m. and 3 p.m. over its inland areas as well as off the western and eastern coasts without approaching close to the inter-Korean border, according to the Joint Chiefs of Staff (JCS). The bombers conducted air-to-ground firing, according to the Yonhap news agency.
In response, the South's Air Force mobilized some 80 fighter jets, including F-35As, in line with full response posture, added the JCS. It is trying to confirm the exact number of North Korean aircraft mobilized.
The North has been fiercely protesting the ongoing combined air drills of South Korea and the United States, called Vigilant Storm.
South Korea and the US were scheduled to end the five-day Vigilant Storm practice on Friday, with around 240 aircraft, including F-35 stealth fighter jets, mobilized around the Korean Peninsula. But they decided to extend it in response to North Korea's firing of an intercontinental ballistic missile (ICBM) on Thursday.
The North accused the allies of pushing the regional security to an "uncontrollable" stage by extending the practice.
Last month, a group of 12 North Korean military aircraft were spotted flying south of a special reconnaissance line set by South Korea. Seoul then scrambled military aircraft, including F-35A fighter jets, in response.
MNA/PR