Despite the decision to retain the two guard posts, the South and the North will withdraw all weapons and other military equipment from them.

"The South's and the North's military authorities will make necessary efforts to ensure that the withdrawal plan will be completed by the end of December while devising measures to enhance mutual trust and transparency in the process of removing the guard posts on a trial basis," the ministry said.

The Koreas' defense ministers signed the inter-Korean military agreement after the third summit between President Moon Jae-in and North Korean leader Kim Jong-un in Pyongyang in September.

The agreement also includes disarming the Joint Security Area in the DMZ, conducting a joint project to excavate Korean War remains in a DMZ battle site and setting up ground, air and maritime buffer zones.

Meanwhile, the defense ministry told an opposition lawmaker that the enforcement of the military agreement is estimated to cost an additional 10.1 billion won ($9.04 million) next year.

The ministry said that it is expected to need some 15 billion won to implement the agreement until next year. It has already set aside around 4 billion won from this year's government budget. But it has not earmarked the 10.1 billion won yet in its budget proposal for next year. (Yonhap)