Kim Yo Jong, the influential sister of North Korean leader Kim Jong Un, has warned of potential new rubbish-filled balloon launches towards South Korea in response to anti-Pyongyang leafleting campaigns.
On Saturday, Kim Yo Jong criticised efforts to infiltrate the North Korean regime and said her government would send more rubbish-laden balloons southward.
North Korea has already dispatched numerous balloons containing refuse such as cigarette butts, cloth scraps and manure across the border since May.
In response, South Korea suspended a 2018 tension-reduction agreement with North Korea and resumed live-fire military drills in border areas.
The escalating tensions highlight the fragile state of inter-Korean relations and the ongoing propaganda battle between the two nations.
The North continued sending balloons throughout June.
In a statement carried by state media, Ms Kim said "dirty leaflets and things of (the South Korean) scum" had been found in border and other areas of North Korea on Sunday morning.
"Despite the repeated warnings of (North Korea), the (South Korean) scum are not stopping this crude and dirty play," she said.
"We have fully introduced our countermeasure in such a situation. The (South Korean) clans will be tired from suffering a bitter embarrassment and must be ready to pay a very high price for their dirty play."
It was not immediately known what was sent into South Korea to draw the wrath of Ms Kim.
For years, groups led by North Korean defectors have floated huge balloons carrying anti-Pyongyang leaflets, USB sticks containing K-pop songs and South Korean drama, and US dollar bills.
