South Korean President Lee Jae Myung has suggested that a civilian was very likely involved in flying drones into North Korea.
The North said it shot down South Korean drones in September last year and on January 4, because they flew into its airspace.
Pyongyang has demanded that the South Korean government apologize for the intrusions and prevent a recurrence.
South Korea’s defense ministry has denied involvement by the country’s military. Police and other authorities are investigating.
Lee said at a Cabinet meeting on Tuesday that although some facts are still unknown, what has been learned so far is that a civilian flew drones into North Korea without consulting authorities.
A South Korean media outlet ran an interview with a man who claims he flew drones into the North from last September.
Lee instructed his defense minister to tighten monitoring near the military demarcation line for drones and other aerial objects.
The president has been seeking an early resumption of dialogue with North Korea.
By calling for prevention of cross-border drone flights, Lee indicated intent to avoid provoking the North.