The Defense Ministry’s conclusion that the two drones recently found near the inter-Korean border came from the North has heightened security concerns, as it indicates the possibility of the communist country launching undetected attacks on facilities in the South using remote-controlled aircraft laden with explosives.

The South Korean military discovered the two unmanned aerial vehicles in frontline areas ― one in Paju, just south of the demilitarized zone, on March 24, and the other on Baengnyeongdo Island, the nation’s westernmost island located close to the maritime border, on March 31.

Military experts who investigated the drones concluded that they were built in the North. They pointed to two words in North Korean spelling inscribed on the back of the lithium-ion battery that powered the drone found in Paju. The two drones were believed to be made using the same mold.

The investigation team also said the North developed them for spying purposes. The drones were both equipped with low-resolution Japanese cameras. To the investigators’ surprise, the one that crashed in Paju contained pictures of Cheong Wa Dae. It was believed to have flown over the presidential office for about 20 seconds.

Investigators said the two crashed drones were so shoddily built that they at first did not look like military spy aircraft. This indicates the North’s drone technology is still rudimentary.

The problem is that they flew into the South undetected. The Defense Ministry said the drone found on Baengnyeongdo Island had been briefly spotted by the military’s low-altitude surveillance radar. But it was depicted not as an aircraft but as a bird due to its small size. The other drone, which was smaller, was not detected by the radar at all.

This indicates the South’s air defense system has a big hole. The North’s spy drones, experts note, are still not advanced enough to carry out terrorism missions. But they say they could still carry 1 kilogram of a biochemical weapon.

And it may be just a matter of time before the North hones its drone technology to the level of being able to launch undetected attacks against the South.

Alarmed by the drones, the military is reportedly considering purchasing advanced low-altitude surveillance radar to spot small, low-flying unmanned aircraft. The military cannot avoid responsibility for its failure to detect the drones, especially the one that flew over Cheong Wa Dae. It needs to take whatever steps necessary to prevent North Korean drones from flying into the South.

The government may also need to consider regulating small remote-control model aircraft used for recreational purposes. Some experienced remote control hobbyists are said to be able to fly their model airplanes over Cheong Wa Dae.