North Korean special forces have carried out an exercise in which they used paragliders to simulate infiltrating behind South Korean lines and launch an attack on the headquarters of the joint South Korean-US military command.

Officials of Seoul's Defence Ministry told Yonhap news that the exercises were conducted over a number of days in mid-September and were the first time that the tactic had been tested by the North.

Special forces troops used paragliders to land on a training ground where a mock-up of the South Korea-US Combined Forces Command in Seoul had been constructed.

The new infiltration technique has caused concern in Seoul, where a defence source said that existing radar systems would be unlikely to detect such small targets crossing the border. Paragliders can also travel swiftly and in silence and would allow the North's special forces to carry out an attack with little warning, particularly at night.

"A paraglider flies at low altitude without making a sound", the official said. It could be useful for making a surprise attack, like a drone.