The decision was made by Seoul after Pyongyang's recent demonstration actions
Another step backward in relations between South and North Korea. Seoul has decided to reinstate military activity on the border, which was limited by a treaty signed in 2018 by then-South President Moon Jae-in and North Korea’s supreme leader Kim Jong-un.
This was in response to North Korea’s launch of several hundred balloons full of garbage and manure that crossed the 38th parallel marking the border between the two countries and flew over the South.
President Yoon Suk-yeol backed the proposal to end the treaty altogether after it was approved by the government following a National Security Council motion against the balloon campaign and GPS signal jamming.
Pyongyang justified sending the balloons in response to similar launches from the South to the North containing messages, flash drives with K-pop movies and songs, and money, food and medicine that are regularly delivered by associations and activists in the South. The North claimed to have launched more than 3000 balloons and 15 tons of trash, they recorded far less in Seoul, but it was enough to further heighten tensions that were already skyrocketing, particularly because of the North’s recent ballistic launches. In any case, Pyongyang has said it is ready to stop launches if the South does the same, “so that Seoul realizes how annoying it is to clean up their garbage.”