South Korea has had enough experience of how unpleasant it is and how much effort it takes to collect rubbish after North Korea sent 15 tonnes of it using 3500 balloons, the North's vice-minister of defence Kim Kang-il said in a statement carried by state media outlet KCNA.
South Korea said it would take "unendurable" measures against North Korea for sending the balloons over the border, which could include blaring propaganda from loudspeakers directed at the North.
The announcement from President Yoon Suk-yeol's office followed a meeting of his National Security Council on a response to what the South said were more than 700 balloons carrying rubbish that North Korea sent over the heavily fortified border to annoy its neighbour.
The council condemned the balloons, and simultaneous GPS jamming, as an "irrational act of provocation".
North Korean balloons carrying rubbish were found across Seoul, authorities in the city say. (AP PHOTO)
South Korea did not rule out resuming the loudspeaker blasts, which it stopped in 2018 after a summit with North Korean leader Kim Jong-un, a senior official at Yoon's office told reporters.
The democratic South and the communist North remain technically at war since the 1950-1953 Korean War ended in an armistice rather than a peace treaty.Â
South Korea is a firm US ally whose sophisticated military regularly holds drills with the United States while the North is developing missile and nuclear technology that the South and the US say violates United Nations resolutions.
North Korea has said its balloons were in retaliation for a propaganda campaign by North Korean defectors and activists in South Korea, who regularly send inflatables containing anti-North Korean leaflets, food, medicine, money and USB sticks loaded with K-pop music videos and dramas across the border.
The North Korean balloons carrying rubbish such as cigarette butts, cloth, paper waste and plastic were found across the capital Seoul from 8pm on Saturday to 1pm on Sunday, South Korea's Joint Chiefs of Staff said.
They said the military was monitoring the starting point and conducting aerial reconnaissance to track down and collect the balloons, which have large bags of rubbish suspended beneath them.
South Korean officers with rifles were picking up and bagging what appeared to be rubbish from the balloons in cordoned-off areas, local media footage showed.
North Korea on Wednesday sent hundreds of balloons carrying rubbish and what was labelled as manure across the border as what it called "gifts of sincerity".
South Korea responded angrily, calling the move base and dangerous.
South Korean Defence Minister Shin Won-sik told US Defense Secretary Austin Lloyd at a conference in Singapore on Sunday that the balloons violated the armistice agreement, according to South Korea's military.
The two reaffirmed a co-ordinated response to any North Korean threats and provocations based on the South Korea-US alliance's combined defence posture, it said.
Emergency alerts were issued in North Gyeongsang and Gangwon provinces and some parts of Seoul on Sunday, urging people not to touch the balloons and to alert police.
