President Lee Jae Myung, left, poses with the Army's 1st Corps commander of duty Lt. Gen. Han Ki-sung at Cheong Wa Dae in Seoul, Jan. 16. Newsis

The defense ministry said Monday it has relieved the Army's 1st Corps commander of duty over his order for the front-line unit to conduct guard operations without live ammunition loaded.

The 1st Corps was found to have instructed soldiers to use unloaded K6 heavy machine guns and K4 automatic grenade launchers while on guard duty while leaving live ammunition next to the firearms. The case has sparked concerns over lax military readiness and security posture at front-line units.

In a notice to the press, the ministry said the Army's 1st Corps commander, responsible for the western front, was excluded from duty starting Monday with regard to the ongoing investigation into the case.