SEOUL—A key symbol of a brief period of detente on the Korean Peninsula half a decade ago is now gone.
This week, North and South Korea suspended an inter-Korean military agreement struck in 2018 to reduce the risk of conflict along the shared border. A liaison office, also dating to that period, was blown up by North Korea in 2020, and any hopes of resurrecting that era’s denuclearization talks have disappeared in a hail of missile launches by Pyongyang.
What’s left is an increasingly belligerent North Korea facing off with a more hawkish government in the South with longstanding guardrails now removed.
The government in Seoul suspended parts of the agreement and said it would resume aerial surveillance along the border after North Korea launched a spy satellite this week. On Thursday, North Korea’s Defense Ministry said it would resume all military activities it had halted under the agreement and vowed it would deploy new weapons along the border.
North Korea has violated the agreement a number of times since denuclearization talks stalled in 2019. Still, the pact provided some protection against escalating tensions in the border region separating the two Koreas. The resumption of live-fire drills and deployment of new troops and weapons could lead to clashes, said Yang Moo-jin, president of the University of North Korean Studies.
“To prove they will no longer abide by the military agreement, North Korea will resume live-fire drills, breach the maritime border and continue with its various missile launches, significantly raising the risk of armed conflict in the border region," Yang said.
The suspension of the agreement signals the end of efforts to halt North Korea’s growing nuclear and missile program and bring Pyongyang back to dialogue, he said.
Tensions between the two Koreas have grown following the election of the conservative government in Seoul and the growing friction between its American ally and North Korea backers Russia and China. Emboldened, Pyongyang has pursued deeper cooperation with Russia and has openly ignored international sanctions.
Before the 2018 pact, North Korea had fired artillery shells at a South Korean island and sank a South Korean vessel with a torpedo attack. North Korean drones crashed near the fortified border after taking photos of military installations. South Korea returned fire on several occasions.
To prevent such incidents, North Korean leader Kim Jong Un and South Korea’s then-President Moon Jae-in agreed to create a no-fly zone along the border, establish buffer zones along their maritime boundary and curb military exercises including live drills within 3 miles of the border.
The two Koreas and the U.S.-led United Nations Command also removed firearms and guard posts from a border village where troops from both sides face off every day. South Korea often limited its response to North Korean provocations to warning shots or messages sent over the inter-Korean hotline.
But since conservative President Yoon Suk Yeol took office last year, South Korea has adopted a policy of responding more aggressively to North Korean military action.
South Korean officials said North Korea had violated the agreement dozens of times, flying drones into the South and conducting live-fire drills near the border. Even before taking office, Yoon said he would suspend the pact if provoked by Pyongyang. Ruling-party lawmakers and military officials have repeatedly called for the agreement to be suspended, citing its limits on South Korea’s ability to identify North Korean threats.
On Wednesday, Yoon approved his National Security Council’s decision to restore surveillance operations along the fortified border after North Korea launched its first military satellite into orbit. The satellite, after two prior failures, successfully reached orbit following technical assistance from Russia, South Korean spy-agency officials told lawmakers on Thursday.
South Korea will be held accountable in the case of an “irretrievable clash" between the two Koreas, North Korean state media reported on Thursday. Pyongyang has said its spy-satellite program is essential to defend against military activities by the U.S. and its allies in the region, blaming joint military exercises and the deployment of U.S. strategic assets for escalating tensions.
The United Nations Security Council bans satellite launches by North Korea, because they are seen as a cover for testing ballistic missile technology. North Korea in recent years has rapidly expanded its weapons program, tested new solid-fuel rocket technology and unveiled new drones.
The two Koreas are chasing independent military-surveillance technology, with North Korea vowing to launch more spy satellites in the near future and South Korea launching its first domestically developed spy satellite Nov. 30 atop a SpaceX Falcon 9 rocket.
In September, on the fifth anniversary of the military pact, Moon criticized the Yoon administration’s talk of suspending the agreement. “Abolishing the inter-Korean military agreement would be irresponsible, akin to removing the last safety pin," the former president said.
On Wednesday, opposition lawmakers and former Moon administration officials said the pact had reduced military tensions significantly in the demilitarized zone and called on the Yoon government to maintain the agreement despite North Korea’s violations.
South Korea’s resumption of aerial surveillance will allow it to track potential surprise attacks from the North, which have become a bigger concern since the Hamas attacks on Israel, said Moon Seong-mook, a retired South Korean brigadier general who was a negotiator at inter-Korean military talks in 2007.
“Until now, South Korea has tried to respect the inter-Korean military agreement," he said, “but now we are warning of retaliation."
Write to Dasl Yoon at dasl.yoon@wsj.com
Only for Subscribers
Unlock the full story and numerous benefits, with an attractive discount. Hurry Now!
Subscribe Now