South Korea on Monday said it tracked “several” drones crossing in from North Korean territory over what is known as the Military Demarcation Line between the two countries, Yonhap news agency reported.
Some reports said one of these North Korean drones had briefly flown over South Korea’s capital city, Seoul.
South Korea’s transport ministry said earlier flights in the day, which were departing from the Incheon and Gimpo airports, had been grounded by the military as a precautionary measure.
The suspension began at 1:08 p.m. (0408 GMT) at Gimpo and at 1:22 p.m. at Incheon and lasted for about an hour before flight departures resumed at around 2:10 p.m., a ministry official told Reuters.
The official did not provide further information about the order.
“Our military first detected a North Korean unmanned aerial vehicle around the Gimpo airspace at 10:25 am,” South Korea’s 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.”
The drones prompted Seoul to fire warning shots and deploy fighter jets and attack helicopters.
One of the jets, a KA-1 light attack aircraft, later crashed in Hoengseong County, Yonhap news agency reported.
This was the first time in five years that North Korean drones have entered South Korean airspace.
Tensions remain high as Seoul continues to hold joint drills with the United States, while Pyongyang, which sees the exercises as a rehearsal for invasion, continues to develop and test its defense tools.
Earlier this week, North Korea fired two short-range ballistic missiles toward the sea off its east coast, less than a week after the country launched two mid-range missiles amid heightened tensions.
It came after the United States and South Korea held a joint air drill on Tuesday and deployed a US B-52H strategic bomber to the Korean Peninsula, according to the South Korean Joint Chiefs of Staff.
North Korea has time and again warned that it will not tolerate US-led war games in the region.
The country has been reeling under multiple UN Security Council sanctions since 2006, however, that has not prevented it from developing its nuclear and missile capabilities as a deterrent against hostile West-led moves.