Defense ministry probes psychological operations unit over unauthorized leaflet missions

Defense Minister Ahn Gyu-back, right, speaks during a meeting of senior military commanders at the Ministry of National Defense in Yongsan, Seoul, Wednesday. Courtesy of the Ministry of National Defense

The Ministry of National Defense has launched an intensive investigation into allegations that the army’s psychological operations unit carried out balloon-borne leaflet missions targeting North Korea without reporting them to its higher command.

The probe includes questioning former and current commanders and conducting on-site inspections of frontline bases, according to military officials familiar with the matter.

The ministry’s Inspection and Investigation Bureau dispatched a team of more than 20 investigators to two units on islands in the West Sea and along the western front line on Monday, following an urgent directive from Defense Minister Ahn Gyu-back. Investigators completed their first round of fieldwork on Wednesday before returning to Seoul for further review.

They later summoned commanders who led the unit between late 2022 and mid-2024 to determine whether unauthorized operations had taken place during their tenure.

The investigation was triggered by testimony from a former enlisted soldier who served in the unit. The soldier told a local newspaper that between October 2023 and early December 2024, the unit carried out more than 10 leaflet drops without alerting its higher command — actions he said could have drawn a military reaction from the North. The testimony also claimed that South Korean forces had conducted leaflet operations even before Pyongyang began sending waste-filled balloons toward the South.

President Lee Jae Myung drew further attention to the case on Monday, posting the report on his social media account and warning that “hidden acts of insurrection” should not be allowed to recur. Military officials say the president also conveyed dissatisfaction with what he viewed as insufficient progress on matters linked to the Dec. 3 martial law declaration last year, including disciplinary actions for officers involved in other recent controversies.

Following the president’s remarks, Ahn ordered additional internal measures. The ministry removed its chief auditor and legal affairs director from their posts after criticism that disciplinary decisions — including those related to the so-called “martial law bus” case and a separate Marine’s death investigation — had been excessively lenient.

The “martial law bus” case involves former Army Vice Chief of Staff Koh Hyun-seok, who allegedly ordered senior officers onto buses and sent them to Seoul during the martial law declaration, as well as 34 other officers now facing disciplinary review. Koh is expected to be referred to a disciplinary board, and several officers have already received revised penalties following government intervention.

The ministry is expected to continue reviewing the unit’s reporting procedures and operational decision-making as it evaluates the initial findings. Officials say further interviews and document checks are likely as the investigation expands to determine how and why the leaflet missions were carried out without authorization.