North Korea’s Latest Offensive: Dumping Trash on South Korea

North Korea has resumed an unusual operation to show anger at South Korea: dumping trash from the sky across the world’s most heavily armed border.

Between Tuesday night and Wednesday, the South Korean military said that it found 260 balloons drifting across the Demilitarized Zone, the buffer between the two Koreas. Soon, residents across South Korea, including some in Seoul, the capital, reported seeing plastic bags falling from the sky.

The authorities sent chemical and biological terrorism response squads, as well as bomb squads, to inspect the payloads. But they only found garbage, like cigarette butts, plastic water bottles, used paper and shoes, and what looked like compost. The South Korean military said the garbage was released by timers when the balloons reached its airspace.

North Korea in recent years has taken an increasingly belligerent military stance. Its unusual offensive this week prompted South Korea to send a cellphone alert to residents living near the inter-Korean border to refrain from outdoor activities and watch out for unidentified objects falling from the sky. Some confusion arose when the alert message included the auto-generated English phrase “Air raid preliminary warning.” The government said it would fix the glitch.

“Acts like this by North Korea are a clear violation of international law and a serious threat to the safety of our people,” the South Korean military said in a statement on Wednesday. “We issue a stern warning to North Korea to stop this anti-humanitarian and dirty operation.”

The North Korean balloons arrived in South Korea days after Pyongyang accused North Korean defectors living in South Korea of “scattering leaflets and various dirty things” over its border counties and vowed to take “tit-for-tat action.”

“Mounds of wastepaper and filth will soon be scattered over the border areas and the interior” of South Korea, Kim Kang Il, a vice defense minister of North Korea, said in a statement on Saturday. “It will directly experience how much effort is required to remove them.”

During the Cold War decades following the 1950-53 Korean War, the two countries waged fierce psychological warfare, bombarding each other with propaganda broadcasts and sending millions of propaganda leaflets across the border.

Such operations ebbed and flowed depending on the political mood on the Korean Peninsula. The two Koreas agreed to de-escalate their propaganda duel after a landmark summit in 2000 at which they agreed to promote reconciliation. The nations again reaffirmed that agreement when the North’s leader, Kim Jong-un, and President Moon Jae-in of South Korea met in 2018.

But North Korean defectors and conservative activists in the South continued to send balloons to the North. Their balloons carried mini-Bibles, dollar bills, computer thumb drives containing South Korean soap operas, and leaflets that called Mr. Kim and his father and grandfather, who ruled the North before him, “pigs,” “vampires” and “womanizers.”

These balloons, their proponents said, helped chip away at the information blackout and a personality cult North Korea imposed against its people.

North Korea took offense, so much so that its military fired antiaircraft guns to shoot down the northbound plastic balloons. In 2016, it retaliated by sending balloons loaded with cigarette butts and other trash, as well as leaflets calling the then South Korean leader, Park Geun-hye, an “evil witch.” A few years later, it claimed that balloons from the South were carrying the Covid-19 virus.

In 2021, South Korea enacted a law that banned the spreading of propaganda leaflets ​into North Korea. The government at the time said that the balloon​s did little more than provoke the North and also created trash in the South because some balloons never make it across the border.

​But last year, the South’s Constitutional Court struck down the law, calling it an unconstitutional infringement on the freedom of speech​.