South Korea’s defence ministry on Tuesday said the country would resume all military activities near the land and sea border.

“All responsibility for causing this situation lies with the North Korean regime and if the North attempts to stage additional provocation, our military will sternly retaliate,” the ministry said in a statement.

South Korean army soldiers patrol along the barbed-wire fence in Paju, near the border with North Korea, on May 31. Photo: AP

The 2018 agreement, signed during a brief period of détente, had already been undermined by both sides amid mounting tensions over the past two years.

In November, the North broke with the 2018 accord and vowed to deploy new weapons along its border with the South after Seoul “partially” suspended part of the pact that established a no-fly zone near the buffer zone in protest against Pyongyang’s launch of a spy satellite.
Earlier this year, North Korean leader Kim Jong-un redefined inter-Korean relations as those of hostile states, abandoning its customary the view of the South as an adversarial but fraternal half of a divided country that would ultimately be reunified.

With the 2018 pact scrapped, both sides will now be able to conduct artillery firing exercises within 5km of the border and resume field manoeuvres at the regimental level or higher. At sea, they can fire artillery and conduct maritime manoeuvres in border waters, despite past clashes in the disputed sea border.

“The scrapping of the 2018 agreement lets military tensions escalate further as both sides have publicly vowed to take stern measures against each other’s presumed hostile activities,” Yang said.

Military personnel collect the debris of balloons sent by North Korea in Incheon, west of Seoul, South Korea, on Sunday. Photo: EPA-EFE/Yonhap

North Korea typically sent around 1,000 leaflet-carrying balloons to the South annually, but it claimed to have launched 3,500 trash-filled balloons across the border over the past week, said Cho Han-bum, a senior research fellow at the Korea Institute for National Unification.

North Korea also continued conducting GPS-jamming attacks along the sensitive sea border in the Yellow Sea, the South’s defence ministry said.

The “full suspension” of the agreement meant that the South could also immediately resume loudspeaker propaganda broadcasts across the border into the North, Cho said.

Pyongyang reacted angrily to the loudspeakers, which blared K-pop songs, news from the outside world and condemnations of the North’s one-man rule, and threatened to destroy the facilities. The loudspeakers were turned off following the 2018 pact.

According to Cho, the loudspeakers are an “effective psychological warfare tool extremely hated by the North” as most of its 26 million people have no access to outside information.

“If the North carries out its threat to shoot at the loudspeakers, the South would have no other alternatives but to respond militarily” as its defence minister Shin Won-sik had ordered the military to retaliate strongly against any North Korean provocative acts, he added.

Members of an organisation of defectors from North Korea send balloons carrying anti-Pyongyang leaflets across the border from the South Korean border city of Paju in April 2016. Photo: EPA-EFE/Yonhap

Accidental clashes stemming from misunderstandings could escalate into a localised war in the absence of a military hotline between the two Koreas, although the North maintains a cross-border communication channel with the US-led United Nations Command, analysts say.

“North Korea has vowed to retaliate against any presumably hostile behaviour by the other side,” said Hong Min, a senior research fellow at the Korea Institute for National Unification Studies.

North Korea said on Sunday it would stop sending trash-carrying balloons into South Korea if Seoul also stopped launching leaflets across the border.

However, activists, including former North Korean defectors, have vowed to continue launching the leaflets.

The South’s Unification Ministry reaffirmed it had no plans to ask the groups to refrain or stop launching leaflets.