"Our military first detected a North Korean unmanned aerial vehicle around the Gimpo airspace at 10:25 am," the Joint Chiefs of Staff (JCS) said in a statement.

"Several North Korean unmanned aerial vehicles invaded our airspace" in the border areas around Gyeonggi province, it added.

The incursion prompted Seoul to fire warning shots and deploy fighter jets and attack helicopters.

One of the warplanes, a KA-1 light attack aircraft, later crashed in Hoengseong County, Yonhap news agency reported.

Flights were temporarily suspended at Gimpo and Incheon international airports near the capital for about an hour at the request of the JCS, according to Yonhap, which cited an official from South Korea's transport ministry.

The incursion is the first time in five years that North Korean drones have invaded South Korean airspace and comes as Pyongyang raises tensions with an unprecedented blitz of weapons tests this year.