The Joint Chiefs of Staff(JCS) have confirmed that one of five North Korean drones that violated South Korean airspace last week briefly crossed into a no-fly zone over the presidential office.

According to an official from the JCS on Thursday, the military’s investigation found that the drone entered the northern fringes of the “P-73” security area.

The official added that there is no safety risk surrounding the top office.

Earlier, the military denied speculation by the opposition and media that the drone had trespassed into the zone, with the JCS expressing "strong regret" over "groundless" claims.