North Korean soldiers crossed the Military Demarcation Line (MDL) dividing the Koreas for at least the third time in recent weeks on Thursday, the South Korean military belatedly reported.

“Yesterday at around 11 a.m., several North Korean soldiers who were working within the central Demilitarized Zone (DMZ) encroached on the MDL, but retreated northward after our military’s warning broadcast and warning shots,” the Joint Chiefs of Staff (JCS) said in a statement to press on Friday morning.

The North Korean soldiers crossed around 65 feet (20 meters) into the South Korean half of the DMZ before retreating, according to ROK