South Korea's defense ministry says North Korean drones crossed the military demarcation line and reached its airspace near the capital Seoul on Monday morning.

The ministry says the unmanned aerial vehicles were detected at around 10:25 a.m. and that the South Korean military fired warning shots. The drones reached Gyeonggi Province near Seoul.

South Korea's Yonhap News Agency reported that the military scrambled jets and other aircraft and opened fire in an attempt to shoot down the drones.

The South Korean airports in Incheon and Gimpo suspended flights for about an hour Monday afternoon in response to a request by the military.

The development comes as Pyongyang continues to develop unmanned aerial vehicles for reconnaissance and air-strike purposes.

Such drones have been displayed at military parades in the past.

In 2014 and 2017, small unmanned North Korean aircraft equipped with cameras were found crashed in the mountains in northern South Korea near the border with the North.