Seoul, South Korea - Trash-carrying balloons sent by North Korea across the border have disrupted more than 100 flights carrying 10,000 passengers, a South Korean lawmaker said Wednesday.

Pyongyang has floated more than a thousand balloons carrying bags of trash into the South, in retaliation for similar missives sent northwards by activists in the South, carrying anti-Kim Jong-un propaganda.

Citing new data from the transport ministry, MP Jeong Jun-ho said that 115 commercial jets have been disrupted by the balloon launches, which began in late May, affecting more than 10,000 passengers.

At least 15 jets, including long-haul arrivals from the US, were forced to make alternative landings, with passengers then driven to Incheon, causing lengthy delays and inconvenience, he said in a press statement.

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Hundreds of passengers on flights from San Francisco, Vancouver, and Los Angeles "were slated to land at Incheon International Airport but ended up at Cheongju Airport without knowing what was happening," he said.

The disruption is "an embodiment of Korea Risk," Jeong said, referring to the term used to describe investor hesitancy over military threats from the North.

He urged authorities to do more to prevent activists from sending the balloons into the North.

South Korea cannot sanction activists sending balloons across the border due to a 2023 court ruling that bans it as an unjustifiable infringement on free speech.

Relations between the two Koreas are at one of their lowest points in years, with Pyongyang ramping up weapons testing as it draws ever closer to Russia, and Seoul stagin frequent military drills alongside Japan and the US.