North Korea has built new uranium facility to expand nuclear arsenal, UN agency says

The International Atomic Energy Agency (IAEA) has voiced “serious concern” over evidence that North Korea has built a facility capable of enriching weapons-grade uranium to bolster its nuclear arsenal.

The new building, located at the the country’s main Yongbyon nuclear facility, can house up to 28 centrifuge cascades – machinery commonly used to enrich uranium – according to a report by the nuclear watchdog released this week.

The regime has also expanded operations at an enrichment site in Kangson, near the capital Pyongyang, according to the report, which was based on analysis of satellite imagery and open-source material, including photographs published by the country’s state media.

The IAEA, whose inspectors were expelled from North Korea in 2009, identified the Yongbyon building as the site’s second uranium enrichment facility after comparing satellite images taken during its construction with media photographs of a visit in early June by the country’s leader, Kim Jong-un.

During his visit, Kim claimed the North’s capacity to produce weapons-grade nuclear material had more than doubled over the past five years, according to state media, promising “vast future plans to exponentially strengthen the country’s nuclear forces”.

Citing a 2025 analysis by the James Martin Center for Nonproliferation Studies in the US, South Korea’s Chosun Daily said the potential 28 cascades comprising 4,592 centrifuges at the Yongbyon facility could yield about 85 kg of weapons-grade highly enriched uranium a year – enough to build three or four additional warheads.

In a statement released this week, the IAEA’s director general, Rafael Grossi, said: “The ongoing operation of enrichment facilities at Kangson and Yongbyon and the reported further expansion of [North Korea’s] production of weapons-grade nuclear material is a cause for serious concern.”

“The continuation and further development” of North Korea’s nuclear programme are “clear violations of relevant UN security council resolutions and are deeply regrettable”, he added.

South Korea’s defence minister, Ahn Gyu-back, said in August that the North possessed between 80 and 120 nuclear warheads – a much higher number than the 57 cited by Donald Trump the same month. The South Korean figure was based on estimates by private research organisations, Ahn told lawmakers, adding that the country’s military could not confirm the numbers.

North Korea has made rapid progress in its ballistic missile and nuclear programmes in recent years, as it demands international recognition as a legitimate nuclear state.

North Korea has conducted multiple long-range missile tests since 2017, the year it last tested a nuclear weapon. In a report submitted to the UN security council in 2020, international experts said the North had “probably developed nuclear devices to fit into the warheads of its ballistic missiles”.