U.N. experts said in key sections of the report that North Korea has also evaded sanctions through "targeted" cyber attacks against officials of countries on the U.N. Security Council and on members of its expert panel.

North Korea has claimed it has no domestic virus cases and has imposed strict quarantine measures and screening at the border.

North Korea has previously ratcheted up fiery rhetoric or conducted weapons tests to wrest outside concessions.

If confirmed, it would be the first case officially acknowledged by North Korean authorities.

The U.S. point man for North Korea met with South Korean officials in Seoul on Wednesday for wide-ranging talks, overshadowed by Pyongyang's insistence that it has no intention of returning to denuclearisation negotiations any time soon.

Trump and North Korean leader Kim Jong Un have met three times since embarking on their high-stakes nuclear diplomacy in 2018. But negotiations have faltered since their second summit in February last year in Vietnam.

Outsiders widely doubt North Korea escaped the pandemic entirely, given its poor health infrastructure and close trade and travel ties to China, where the coronavirus emerged late last year.

The activists have sent leaflets and plastic bottles filled with rice across the border, prompting North Korea to raise provocations with the South.

North Korea abruptly used Park Sang-hak's leaflet campaign as a justification for a series of provocative steps against South Korea.

It was not immediately clear why North Korea had softened its position, which came after it blew up a liaison office last week and cut off communication hotlines with the South.