North Korean soldiers working in the Demilitarized Zone separating the two Koreas briefly crossed into the South again on June 18 before returning to their side after the South fired warning shots, the Joint Chiefs of Staff (JCS) said, Report informs referring to Yonhap.

It marked the North’s second border violation in less than two weeks after a similar incident on June 9.

Around 20 to 30 North Korean soldiers carrying work tools crossed the Military Demarcation Line (MDL) within the DMZ in the central section of the border at around 8:30 a.m., according to the JCS.

The South Korean military conducted warning broadcasts and fired warning shots, prompting the North Korean soldiers to return to their side of the border, the JCS said, adding that there was no unusual activity after the warning shots.

A JCS official said the incident appears to be another accidental incursion following the June 9 incident.

Earlier this month, some 20 to 30 North Korean soldiers briefly crossed the border at around 12:30 p.m. before retreating back to the North after the South fired warning shots. Four other North Korean soldiers shortly made another incursion but soon returned to the North after similar measures.

“Our military is thoroughly monitoring the North’s activities in the border area amid close cooperation with the United Nations Command,” the official said.