South Korea is accusing North Korea of sending more than 150 balloons carrying "filth and garbage" over the countries' shared border in retaliation against a long-standing leafleting campaign by pro-democracy activists in the South.
Citizens were alerted by South Korean armed forces that "suspicious objects" believed to be from North Korea were "identified in the front-line areas" late on Tuesday night, according to the Financial Times.
Seoul released images of large white balloons carrying bags as well as garbage from one of the balloons scattered over a highway in a western district of the South Korean capital.
Unverified media reports in South Korea allege some of the bags contained animal feces.
"This move by North Korea is a clear violation of international law and seriously threatens the safety of our people," the South Korean Joint Chiefs of Staff said in a statement.
"We issue a stern warning that it must immediately stop its anti-humanitarian and low-level actions."
The balloon droppings follow North Korea's Vice Defense Minister Kim Kang Il's warning on Sunday that Pyongyang would respond to balloon launches by South Korean activists by distributing "mounds of waste paper and filth over border areas and the interior of [South Korea]."
Pyongyang has long criticized South Korea for allowing its activists to release balloons into the North carrying items ranging from anti-regime leaflets and electronic devices to medication and Bibles.
The practice was initially banned by Moon Jae-in, South Korea's former left-wing president, but was tolerated under the country's conservative administration until the ban was thrown out altogether by its constitutional court last year.
In 2022, Pyongyang blamed the balloons for a massive coronavirus outbreak in the country, attributing a rise in cases to "alien things coming by wind."
North Korea sent five unmanned aerial vehicles into South Korean airspace later that year, with one surveillance drone breaching a special no-fly zone surrounding the South Korean president's office and the headquarters of the country's joint chiefs of staff.
Peter Ward, a research fellow at the Sejong Institute think tank in Seoul, explained,
"North Korea regards the balloons from the South as acts of psychological warfare and perhaps even as attempts to probe the effectiveness of their air defenses, and so they respond in kind."
On Monday, North Korea attempted to launch a military reconnaissance satellite into space; however, the attempt failed after the rocket exploded shortly after liftoff.
While North Korea claims to have successfully launched its first military spy satellite into orbit last year, the regime's leader Kim Jong Un vowed on Tuesday to press on with the program, calling South Korea's condemnation of this week's launch "hysterical."
"Despite the advances North Korea has made with its satellite program, its technical sophistication still leaves a lot to be desired," said Ward.
"Much easier to launch a sack full of dung instead," Ward remarked.
