This development follows the recent launch of a military spy satellite by North Korea.
The alleged military activities are a response to South Korea's decision to partially suspend a 2018 agreement aimed at reducing military confrontations along the front-line. This decision was triggered by the launch of the Malligyong-1 satellite on November 21, as reported by the Associated Press.
The 2018 agreement stipulated that both Koreas cease aerial surveillance and live-fire exercises in designated no-fly and buffer zones along the Demilitarized Zone (DMZ). It also required the removal of some front-line guard posts and land mines. Following the agreement, South Korea retained 50 border guard posts, while North Korea kept 150.
In the wake of North Korea's claim of successfully placing its first military spy satellite into orbit, South Korea announced a partial suspension of the agreement and a resumption of aerial surveillance along the DMZ. South Korea justified its actions as "a minimum defensive measure," arguing that the satellite launch indicated North Korea's intent to enhance its surveillance of the South and improve its missile technology.
North Korea, however, swiftly criticized South Korea's decision and threatened to deploy powerful weapons at the border in retaliation, according to the Associated Press.
On Monday, South Korea's military released images purportedly showing North Korean soldiers erecting new guard posts. The South Korean Defense Ministry has stated that it is prepared to "promptly and strongly punish" any provocations from the North.
South Korea's Joint Chiefs of Staff acknowledged the apparent success of the Malligyong-1 satellite launch last Wednesday, but stopped short of confirming its operational status. "After a comprehensive analysis of its flight path and other signs, the satellite is assessed to have entered into orbit," they stated.
North Korean state media subsequently claimed that the satellite has supplied its leadership with images of key South Korean and U.S. bases, including the Pearl Harbor naval base and Hickam Air Base in Honolulu.