"Some North Korean soldiers working within the DMZ on the central front briefly crossed the Military Demarcation Line," the JCS said in a statement, referring to the line of control in the heavily fortified border between the two Koreas.
"After our military issued warning broadcasts and warning shots, they retreated northward," it said, adding the incident happened June 9.
"Apart from the immediate retreat of the North Korean soldiers following our warning shots, there were no unusual movements observed", the JCS said, adding the military was closely monitoring troops near the border.
Tensions between the two Koreas -- which remain technically at war since the 1950-1953 conflict ended in an armistice rather than a peace treaty -- are at one of their lowest points in years.
In recent weeks, North Korea has sent hundreds of balloons laden with trash like cigarette butts and toilet paper southward, in what it calls retaliation for balloons carrying anti-Pyongyang propaganda sent north by activists.
The South Korean government this month fully suspended a 2018 tension-reducing military deal and restarted loudspeaker propaganda broadcasts along the border in response to the trash balloons, infuriating the North, which warned Seoul was creating "a new crisis".
South Korea's military said Monday it had detected signs the North was installing its own loudspeakers.
North Korea had used loudspeakers along the border since the 1960s, typically broadcasting praise of the Kim family, but suspended their use in 2018 as ties warmed.
AzVision.az
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