North Korean special forces have been training to invade South Korea with paragliders, according to South Korea's Yonhap news agency.
The drills were conducted in mid-September at a training site with a building modelled after the South Korea-US Combined Forces Command in Seoul, Yonhap reported.
Special forces from North Korea's navy, air force, 11th army corps, and sniper brigade participated, according to Newsweek.
Paragliders can fly below radar and can also be folded down and transported easily.
"A paraglider flies at a low altitude without making a sound. It could be useful for making a surprise attack, like a drone," a South Korean defence official told Yonhap.
"I believe that North Korean special forces are adopting amazing methods of infiltration with limited resources," the official said.
The US and South Korea, in response, conducted their own short-range air-defence drills, known as SHORAD, in late September to thwart "low altitude cruise missiles, unmanned aerial systems and air breathing threats," Newsweek reported, citing a US Army press release.
The joint drills were aimed at defending "a critical location, de-conflicting engagements of enemy aircraft based on sector of fire, and utilising secondary means of targeting enemy aircraft when their primary weapon system becomes combat ineffective," the US Army said, adding that the drills included "scout helicopters and a perimeter attack by ROK Special Forces."
South Korean Gin Gliders, one of the world's largest producers of paragliders, used to operate in the Kaesong Industrial Complex, which is a collaborative economic area between the North and South. Seoul closed the complex in early 2016 in response to North Korea's missile tests.
Pyongyang, however, reopened the plant last week despite Seoul's objections, according to Newsweek.
The US Army said it will continue the SHORAD drills in the coming months.