South Korea scrambled fighter jets and attack helicopters and fired warning shots on Monday after North Korean drones violated its airspace, the South's Yonhap news agency reported.

South Korea tracked the drones crossing from North Korea over what is known as the Military Demarcation Line between the two countries, Yonhap reported.

South Korea's transport ministry said earlier that flights departing from its Incheon and Gimpo airports were suspended following a request from the military.

The suspension began at 1:08 p.m. at Gimpo and at 1:22 p.m. at Incheon and lasted for about an hour before departures resumed at around 2:10 p.m., a ministry official said.

The official did not provide further details on the suspension.