Seoul, South Korea - A North Korean balloon carrying trash landed on Seoul's presidential compound Thursday, authorities said, with local media reporting it contained propaganda leaflets ridiculing President Yoon Suk Yeol and his wife.

Activist groups in South Korea have long sent propaganda northwards, typically carried by balloons, including leaflets, US dollar bills, and sometimes USB drives containing K-pop or K-dramas, which are banned in the tightly controlled North.

North Korea has been bombarding the South with trash-carrying balloons since May, in what it says is retaliation for the activists' propaganda missives.

A balloon from the North "exploded in the air, and the fallen debris was identified scattered around the Yongsan office area" early Thursday morning, the Presidential Security Service said in a statement sent to AFP, referring to the presidential compound.

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The service added that a safety inspection confirmed "it posed no dangerous risk or contamination."

It marks the second time the South Korean leader's office in downtown Seoul, which is protected by scores of soldiers and a no-fly zone, has been directly hit by balloons launched from the North, with the first incident occurring in July.

South Korea's Chosun Daily reported the balloon carried anti-South leaflets ridiculing South Korean President Yoon and his wife Kim Keon Hee.

The leaflets included photographs of the couple along with phrases such as: "It's fortunate that President Yoon and his wife have no children" and "South Korea is the Kingdom of Keon Hee."

The South Korean first lady, Kim Keon Hee, faces allegations of participating in a stock manipulation scheme and meddling in the conservative ruling People Power Party's candidate nominations in the lead-up to the April general elections.

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The South Korean military declined to confirm the report when asked by AFP.

The incident comes days after Kim Yo Jong, the powerful sister of North Korean leader Kim Jong Un, once again accused South Korean activists of sending anti-Pyongyang materials into the North, and South Korea of sending unmanned drones to its capital Pyongyang.

"Seoul will have to experience at first hand so as to know properly how dangerous act it committed and how terrible and fatal the consequences it brought on itself are," she said.