This archive report was first published on 16 June 2020.
North Korea's military has been on high alert, with the General Staff saying it is ready to 'rapidly and thoroughly' implement any decisions by the government.
The move comes after the sister of North Korean leader Kim Jong-un, Kim Yo-jong, threatened military action against South Korea on Saturday.
Kim Yo-jong said she had instructed the military to prepare for the step, and the North Korean military has now said it is ready to 'turn the front line into a fortress and heighten military vigilance'.
South Korea's defence ministry has responded by saying it is working with the US to closely monitor military moves in the North.
The tensions between the two countries have been rising for some time over the cross-border leaflets, usually sent via balloons.
North and South Korea are separated by the so-called demilitarized zone (DMZ) – a buffer along the border that has separated the two countries since the Korean War in the 1950s.
