A guard post at the border with the North in Goseong County, eastern Gangwon, could be the first to be re-established by South Korea as the two Koreas walk back their landmark 2018 military agreement.

The post in Goseong, the first that the South established in the demilitarized zone (DMZ) following the 1953 Korean War armistice, will be the first to be remanned after the two Koreas dismantled 10 guard posts each in the DMZ five years ago to reduce tensions, according to multiple military sources.

Of South Korea’s 60 guard posts in the demilitarized zone, 10 were dismantled in 2018 as South Korea followed through with the inter-Korean military agreement of 2018 to set up a buffer zone between the two Koreas to reduce the chance of accidental clashes.

The one in Goseong was not dismantled, but soldiers and arms were withdrawn.

The North did the same, dismantling 10 of its 160 guard posts in the DMZ and withdrawing soldiers and arms from one.

Tensions between the two Koreas have flared in recent weeks, with the North launching a military spy satellite last week in violation of multiple UN Security Council resolutions.

After South Korea partially suspended the military agreement, North Korea announced it was scrapping the deal altogether, and its soldiers were seen building makeshift watch towers and carrying large firearms into the demilitarized zone, according to the Defense Ministry in Seoul.

Pyongyang was reportedly rebuilding the guard post closest to the Goseong guard post as of Wednesday.

The South Korean military said it will closely watch the North’s rebuilding process and decide whether to rebuild any of the 10 dismantled guard posts.

The North’s state-run Korean Central News Agency announced last week the successful launch of a reconnaissance satellite, the Malligyong-1, mounted on a Chollima-1 rocket, from the Sohae satellite launching station in Cholsan County, North Pyongan Province.

President Yoon Suk Yeol and Defense Minister Shin Won-sik levied strong criticism against the North, with the defense chief vowing to respond to military provocations from the North “without hesitation.”

A U.S. State Department spokesperson said the North Korean actions in the DMZ following the suspension of the agreement are “increasing the risk of military tensions and miscalculations on the Korean Peninsula,” according to Yonhap.

BY ESTHER CHUNG [chung.juhee@joongang.co.kr]