The United Nations nuclear watchdog has confirmed that North Korea has constructed a new two-storey uranium enrichment facility at its main Yongbyon nuclear complex, warning that the development represents a significant and troubling expansion of the country's weapons-grade nuclear material production. The International Atomic Energy Agency (IAEA), which has been denied access to North Korea since its inspectors were expelled in 2009, based its findings on satellite imagery, open-source material, and photographs released by North Korean state media.

The new building at Yongbyon — a sprawling nuclear complex located roughly 100 kilometres north of the capital Pyongyang — is capable of housing up to 28 centrifuge cascades, the machinery used to enrich uranium to weapons-grade levels. Analysts at the James Martin Center for Nonproliferation Studies estimate that if fully operational, those 4,592 centrifuges could produce around 85 kilograms of highly enriched uranium per year — enough for three to four additional nuclear warheads annually. Separately, the IAEA also identified the start of operations at an expanded annex of a second enrichment site in Kangson, near Pyongyang, which first appeared in satellite imagery in 2024. IAEA Director General Rafael Grossi called the findings "a cause for serious concern," stating that the "continuation and further development" of North Korea's nuclear programme constitute "clear violations of relevant UN Security Council resolutions."

The disclosure followed a visit in early June by North Korean leader Kim Jong-un to what state media described as a "newly inaugurated nuclear materials production factory." Kim claimed the country's capacity to produce weapons-grade material had more than doubled over the past five years and promised "vast future plans to exponentially strengthen the country's nuclear forces." Estimates of the North's current arsenal vary: South Korea's defence minister cited figures of between 80 and 120 warheads, based on assessments by private research organisations, while US President Donald Trump referenced a figure of 57 in a separate statement. North Korea has conducted six nuclear weapons tests in total, the last in September 2017, and has carried out numerous intercontinental ballistic missile tests since, with some assessed as capable of reaching the western United States.

Experts warn that the programme's opaque nature makes it especially difficult to counter. "What makes North Korea's nuclear programme so concerning is that many of its facilities are unknown, concealed, and thus difficult to target," said Edward Howell, a lecturer at the University of Oxford. "Beyond Yongbyon, we know that other facilities exist. The embeddedness of North Korea's nuclear doctrine within its foreign and domestic policy means that we should expect there to be more concealed production sites."

The expansion comes as North Korea's geopolitical standing has shifted considerably. International sanctions, imposed over the nuclear programme, have been widely circumvented, with trade between Pyongyang and Beijing continuing openly. Since late 2024, North Korea has dispatched an estimated 15,000 soldiers to support Russia in its war in Ukraine, receiving in return security guarantees, economic assistance, and military technology. Experts caution, however, that this alignment with Moscow and Beijing carries risks of its own, including deep dependency on China and the uncertainty of Russian commitment should the Ukraine conflict end. South Korea, meanwhile, appears to be recalibrating its approach: its government has signalled that dialogue and trust-building must come before any attempt to negotiate over the North's nuclear arsenal — an implicit acknowledgement of how substantially the strategic landscape has changed.