SEOUL, South Korea (AP) — A South Korea activist said Thursday he launched more huge balloons carrying COVID-19 relief items toward North Korea, days after the North vowed to sternly deal with such activities and made a highly questionable claim they were a source of the virus.

South Korean experts doubt North Korea’s moves to blame South Korean balloons and say the intent might be to incite anti-South Korea sentiments and ease public complaints over its handling of the outbreak. The coronavirus is spread by people in close contact who inhale airborne droplets, and the expert consensus is that the spread of the virus from surfaces is virtually impossible.

Park Sang-hak, a North Korean defector-turned-activist, said his group floated 20 balloons carrying 20,000 masks and tens of thousands of vitamin C and fever-reducing tablets from a South Korean border town on Wednesday. He said he sent similar aid items by balloon across the inter-Korean border twice last month.

One of the balloons carried a large placard calling North Korea leader Kim Jong Un “a hypocrite” and condemning him for holding South Korean activists responsible for the virus outbreak. But Park said the balloons didn’t carry what he had previously sent for years — small but numerous anti-North Korea propaganda leaflets, U.S. one-dollar bills and USB sticks containing information about the outside world. He said he’ll now focus on sending medical relief items because North Koreans urgently need them.

Since North Korea in May admitted to an omicron outbreak of the virus, its state media said about 4.8 million North Koreans have developed fevers but only 74 have died. Experts doubt the figures are accurate and speculate its disclosure of an extremely low death count is tooled to prevent political damage to Kim.

Last week, state media said the outbreak had been traced to residents who had contact with “alien things” in a town near the border and that authorities have been ordered “to vigilantly deal with alien things coming by wind and other climate phenomena and balloons.”

Some outside experts, however, believe the omicron variant entered North Korea when it briefly reopened its northern border with China for freight traffic in January. Observers say the virus spread further when many North Koreans travelled to Pyongyang for massive public events marking state anniversaries in April and returned home.

“The one who spread COVID-19 is Kim Jong Un. But since public sentiments are really bad, he’s trying to put all the blame on us,” Park said. “How can materials spread COVID-19?”

Park is standing trial for a past leafleting campaign under a contentious South Korean law criminalizing such activities that took effect last year.

Park said he hasn’t been contacted by authorities about his recent ballooning activities. Police said Thursday they are investigating Park’s recent balloon launches but refused to provide further details.

North Korea is extremely sensitive to outside attempts to criticize Kim’s rule to people who has little access to information from foreign sources. In 2014, North Korea fired at balloons flying toward its territory, and in 2020 it destroyed an empty South Korean-built liaison office in the North to express its anger over leafleting.

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