North Korea has floated another 600 trash-filled balloons across the border, the South's military said Sunday, with personnel in hazmat suits seen collecting piles of rubbish containing everything from cigarette butts to bits of cardboard and plastic.
South Korea has called the latest provocation from its nuclear-armed neighbour "irrational" and "low-class" but, unlike the spate of recent ballistic missile launches, the trash campaign does not violate UN sanctions on Kim Jong Un's isolated regime.
Seoul has warned of strong countermeasures unless the North stops the balloon bombardment, saying it runs counter to the armistice agreement that ended the 1950-53 Korean War hostilities.
South Korea's Joint Chiefs of Staff called on the public to stay away from the rubbish heaps, though "no hazardous substances have been found."
Around 900 balloons have been sent southwards by Pyongyang since Tuesday, the JCS said, adding that the latest wave began arriving late Saturday.
As of around 10 am (0100 GMT) on Sunday, "approximately 600 balloons have been identified, with about 20 to 50 balloons per hour moving through the air".
The balloons are landing in northern provinces, including the capital Seoul and the adjacent area of Gyeonggi, which are collectively home to nearly half of South Korea's population.
The latest batch of balloons have been full of "waste such as cigarette butts, scrap paper, fabric pieces and plastic," JCS said.
"Our military is conducting surveillance and reconnaissance from the launch points of the balloons, tracking them through aerial reconnaissance, and collecting the fallen debris, prioritising public safety," it said.
"We urge the public to avoid contact with the fallen waste balloons and report them to the nearest military unit or police station," it added.
South Korea's National Security Council is expected to meet on Sunday to discuss a plan to respond to the balloons by resuming loudspeaker propaganda campaigns along the border with North Korea, Yonhap reported.
In the past, South Korea has broadcast anti-Kim propaganda into the North, which infuriates Pyongyang.
Activists in the South have also floated their own balloons over the border, filled with leaflets and sometimes cash, rice or USB thumb drives loaded with K-dramas.
Earlier this week, Pyongyang described its "sincere gifts" as a retaliation for the propaganda-laden balloons sent into North Korea.
"If Seoul chooses to resume anti-North broadcast via loudspeakers along the border, which Pyongyang dislikes as much as anti-Kim balloons, it could lead to limited armed conflict along border areas, such as in the West Sea," said Cheong Seong-chang, director of the Korean peninsula strategy at Sejong Institute.
In 2018, during a period of improved inter-Korean relations, both leaders agreed to "completely cease all hostile acts against each other in every domain", including the distribution of leaflets.
South Korea's parliament passed a law in 2020 criminalising sending leaflets into the North, but the law -- which did not deter the activists -- was struck down last year as a violation of free speech.
Kim Jong Un's sister Kim Yo Jong -- one of Pyongyang's key spokespeople -- mocked South Korea for complaining about the balloons this week, saying North Koreans were simply exercising their freedom of expression.
The two Koreas' propaganda offensives have sometimes escalated into larger tit-for-tats.
In June 2020, Pyongyang unilaterally cut off all official military and political communication links with the South and blew up an inter-Korean liaison office on its side of the border.
The trash campaign comes after analysts have warned Kim is testing weapons before sending them to Russia for use in Ukraine, with South Korea's defence minister saying this weekend that Pyongyang has now shipped about 10,000 containers of arms to Moscow, in return for Russian satellite know-how.
