North Korea is making a "very serious" advance in its ability to produce nuclear weapons, the head of the United Nations' nuclear watchdog has warned, with new satellite imagery and agency assessments pointing to a significant ramp-up in activity at the country's main nuclear complex.
Rafael Grossi, director-general of the International Atomic Energy Agency (IAEA) — the UN body responsible for monitoring global nuclear activity — made the warning during a visit to Seoul on Wednesday. Speaking to reporters, he confirmed a rapid rise in operations at the Yongbyon nuclear site, North Korea's primary nuclear facility located roughly 90 kilometres north of the capital Pyongyang. Activity had intensified across Yongbyon's 5-megawatt reactor, its reprocessing unit, its light-water reactor, and additional facilities. The IAEA also noted the construction of a new uranium enrichment facility comparable in scale to the existing one at Yongbyon — a development that, Grossi said, pointed to a "significant increase in the enrichment capacity" of the country, officially known as the Democratic People's Republic of Korea (DPRK). North Korea is currently estimated to possess several dozen nuclear warheads, with some analysts putting the figure at around 50, though experts remain divided over whether Pyongyang has successfully miniaturised warheads for delivery on long-range ballistic missiles.
The US think tank Beyond Parallel, based at the Center for Strategic and International Studies in Washington, said this week that satellite imagery suggested a newly constructed enrichment building at Yongbyon was nearing operational readiness. A second suspected enrichment site at Kangson, near Pyongyang, has also not been declared to international nuclear authorities. Both facilities, analysts warn, could substantially increase North Korea's annual weapons-grade uranium output. South Korea's President Lee Jae Myung said in January that the North was already producing enough material for 10 to 20 new nuclear weapons per year.
North Korea conducted its first nuclear test in 2006 and has been under a series of UN Security Council sanctions ever since. It expelled IAEA inspectors in 2009 and has repeatedly declared that it will never abandon its nuclear arsenal, which leader Kim Jong Un views as essential to regime survival and a deterrent against foreign intervention. Diplomatic efforts to constrain the programme have largely stalled: summits between Kim and Donald Trump during Trump's first presidency produced no lasting agreement, and relations between Pyongyang and Seoul remain frozen. North Korea has not carried out a nuclear test since 2017, though it has continued to advance its missile capabilities.
Why this matters: North Korea's accelerating nuclear build-up raises the prospect of a qualitative shift in regional and global security. Should Pyongyang achieve a large, reliable arsenal paired with intercontinental ballistic missiles capable of reaching the United States, its leverage in any future negotiations would grow substantially. South Korea's president has warned that once North Korea has more nuclear material than it needs for its own deterrence, the risk of proliferation — selling or transferring weapons or technology abroad — becomes a serious global concern. For now, the IAEA, which has been locked out of North Korea for over 15 years, can only monitor the situation from the outside, limiting the international community's ability to assess the full scale of the threat.