North Korea’s nuclear machine is getting bigger: A new uranium facility, thousands of centrifuges and missiles capable of reaching America reveal how Kim Jong Un is changing the threat

For years, North Korea's nuclear programme has been difficult to measure because much of it operates behind secrecy, restricted access and carefully controlled state propaganda. Now, satellite imagery and photographs released by Pyongyang have provided another glimpse of how that programme is growing.

At the centre of the latest concern is a new two-storey uranium-enrichment building at Yongbyon, North Korea's principal nuclear complex. The International Atomic Energy Agency (IAEA) says the facility appears capable of accommodating as many as 28 centrifuge cascades, the arrangements of centrifuges used to increase the concentration of uranium-235. The agency has described the continued development of North Korea's enrichment infrastructure as a matter of "serious concern".