SEOUL, South Korea — North Korea has begun rebuilding guard posts and bringing heavy firearms along the border with South Korea, after scrapping a 2018 inter-Korean military tension reduction deal, Yonhap News Agency reported Monday, citing the Defense Ministry.

Ministry officials disclosed photos showing North Korean troops installing temporary guard posts, carrying what appeared to be recoilless guns, and standing guard at night inside the Demilitarized Zone (DMZ) separating the two Koreas.

These moves come after the North Korea said last week, it would restore all military measures halted under the 2018 tension reduction deal.

The Comprehensive Military Agreement was signed in September 2018, at the height of a reconciliatory mood when then South Korean President Moon Jae-in traveled to Pyongyang for summit talks with North Korean leader Kim Jong-un.

The deal called for demolishing border guard posts within one kilometer of the border, banning military drills and maneuvers near the land and sea borders, and establishing no-fly zones along the border, among a series of measures designed to reduce military tensions.

At the time, both sides demolished 10 guard posts each and withdrew troops and weapons from them.

In response to Pyongyang’s latest move, Seoul’s Defense Ministry vowed to keep close tabs on the North’s activities to detect sings of provocations along the border.

Gen. Kim Myung-soo, the new chairman of the Joint Chiefs of Staff who took charge Saturday, said the South Korean military will take “corresponding measures” in response to the North’s latest move, without elaborating on details.

“It depends on the enemy’s behavior. It is North Korea that has taken actions and broken trust. We will take corresponding measures,” Kim said during his first meeting with reporters on Monday.

North Korea’s move is seen as part of Pyongyang’s ongoing pressure campaign against Seoul and potentially sets the stage for future provocative activities at the frontline between the two states.

The South Korean military revealed images of what appears to be the North’s new Observation Posts across the 11 guard posts Monday. A military official said the authorities also spotted North Korean troops, trenches as well as weapons, such as recoilless rifles.

North Korea reinitiated its pressure campaign against the South last week when it declared an immediate and complete withdrawal of the military agreement.

Pyongyang’s decision came just a day after South Korea suspended the landmark 2018 inter-Korean military agreement as a countermeasure to Pyongyang’s illegal satellite launch that violated a United Nations Security Council resolution.

Cheon Seong-whun, a former security strategy secretary for South Korea’s presidential office, sees escalated tensions in the Korean peninsula to be inevitable in the short term.

“North Korea’s actions appear to be a demonstration of their intentions, as they declared last week. They can fire artillery in the West Sea [Yellow Sea] or further restore additional guard posts. This could temporarily escalate tensions on the Korean Peninsula,” Cheon said.

Earlier on Monday, North Korea blamed the United States and South Korea for forcing it to scrap the inter-Korean military agreement.

North Korea has repeatedly expressed its unease with the intensifying trilateral collaboration among the US, South Korea, and Japan in the region. Pyongyang perceives this alliance as a threat to its regime’s security, primarily because it cannot match the advanced military capabilities of these allies.

The US, South Korea, and Japan are currently conducting maritime exercises near the South Korean island of Jeju since Sunday, aimed at strengthening close coordination and operational capabilities, according to the South Korea’s Defense Ministry. — Agencies