The move prompted the deployment of fighter jets, choppers and other assets to shoot them down.

The South's military detected multiple "unidentified objects," presumed to be unmanned aerial vehicles, in border areas of Gyeonggi Province from 10:25 a.m., according to an official at the Joint Chiefs of Staff as quoted by Yonhap news agency.

The vehicles flew across the Military Demarcation Line separating the two Koreas, and were spotted flying in those areas in Gimpo, Ganghwa Island and Paju, leading to temporary suspensions of civilian flights.

The South issued warning messages, fired warning shots, and scrambled fighters, attack helicopters and other warplanes to remove them, while it remains unconfirmed whether the vehicles carry any weapons, the official said.

"We also identified them with our eyes," the JCS official told reporters as quoted by Yonhap on condition of anonymity. "An operation is still ongoing against the vehicles."