UNITED NATIONS (AP) -- U.N. experts say North Korea is paving the way for additional nuclear tests with new preparations at its northeastern test site and continues to develop its capability to produce a key ingredient for nuclear weapons.
The experts also said in key excerpts from their latest report obtained late Thursday by The Associated Press that North Korea conducted two major hacks this year, resulting in the theft of cryptocurrency assets worth "hundreds of millions of dollars."
They said Pyongyang also continues illicitly importing oil and exporting coal in violation of U.N. sanctions, using the same companies, networks and vessels.
South Korean and U.S. intelligence officials have said they detected North Korean efforts to prepare its northeastern Punggye-ri testing ground for another nuclear test. It would be the North's seventh since 2006 and the first since September 2017, when it claimed to have detonated a thermonuclear bomb to fit on its intercontinental ballistic missiles.
The panel of experts' report to the U.N. Security Council provides some details of the work being carried out at the site by the Democratic People's Republic of Korea, the country's official name.
The experts said they observed that the DPRK started re-excavation work in March at the entrance to Tunnel 3 at Punggye-ri "and reconstructed support buildings originally dismantled in May 2018."
"Satellite imagery showed increased numbers of vehicle tracks around this secondary entrance from mid-February 2022, followed by construction of a new building adjacent to the entrance at the beginning of March," the panel said. "A pile of lumber, for possible use in the construction of the tunnel structure, was also detected around the same time."
It added that, "Piles of soil from the tunnel excavation around the entrance were observed during this period."
"Work at the Punggye-ri nuclear test site paves the way for additional nuclear tests for the development of nuclear weapons," the experts said, adding that this is an objective stated at the Eighth Congress of the country's ruling Workers' Party of Korea in January 2021.
In another aspect of the DPRK's nuclear program, analysts said satellite images last September showed that North Korea was expanding a uranium enrichment plant at its main Yongbyon nuclear complex, a sign that it wanted to boost production of the key bomb material.
The U.N. experts said in the new report: "DPRK continued to develop its capability for the production of nuclear fissile materials at the Yongbyon site."
Nuclear negotiations between the United States and North Korea have stalled since 2019 over disagreements over the DPRK demand to lift crippling U.S.-led sanctions and Washington's demand for significant steps by Pyongyang toward nuclear disarmament.
North Korean leader Kim Jong Un has expanded his ballistic missile program amid the diplomatic pause, and analysts say another nuclear test would escalate his brinkmanship aimed at cementing the North's status as a nuclear power, and negotiating economic and security concessions from a position of strength.
The panel of experts said the DPRK continued to accelerate its missile programs, launching 31 missiles "combining ballistic and guidance technologies," including six ICBMs and two "explicitly described as ballistic weapons." It said the DPRK also claimed to have advanced its development of "tactical nuclear weapons."