The Republic of Korea (ROK)'s joint military-police investigative body on Tuesday raided 18 locations as part of a probe into allegations of unauthorized civilian drone flights from the ROK into the Democratic People's Republic of Korea (DPRK).

Military and police investigators launched simultaneous raids on 18 sites, including the Defense Intelligence Command and the National Intelligence Service (NIS), from about 9 a.m. local time.

The joint military-police investigation task force investigated three civilian suspects on charges of aiding the enemy, alongside violation of the aviation safety act.

The task force additionally booked three active-duty military personnel and one NIS official as suspects, believing that they were involved in the unauthorized drone flights.

The DPRK had accused the ROK of violating its airspace by flying a drone into its territory on January 4.