ANKARA

A team from South Korea's special counsel raided several locations Monday over allegations that former President Yoon Suk Yeol ordered a covert drone incursion into North Korea to provoke a military response to justify his martial law decree last December, local media reported.

The move indicates that an ongoing insurrection investigation against Yoon for his failed martial law bid has expanded into treason charges, Yonhap News Agency reported.

Investigators raided 24 locations including the country's Drone Operations Command (DOC) and the Ministry of Defense as well as the Defense Counterintelligence Command to obtain evidence related to the case.

They also carried out raids at the National Security Office of the presidential office and the residence of Maj. Gen. Kim Yong-dae, the head of the drone command.

The special counsel suspects that Yoon ordered the military to send the drones to Pyongyang last October.

Investigators are also looking into allegations that the military was involved in the cover-up of the drone operation.

They have reportedly secured a recording of a military officer suggesting that Yoon directly instructed the drone command to prepare a drone mission across the border into Pyongyang between October and November last year, weeks before he declared martial law.

The DOC is also accused of deliberately modifying a drone to carry anti-North Korea leaflets despite knowing the risk of it crashing to the ground.

In October last year, Pyongyang said it discovered the remains of the drone carrying the leaflets, warning that it would retaliate if Seoul did it again.