N Korea has built two-storey uranium enrichment facility, says watchdog
The International Atomic Energy Agency's says the facility is cause for "serious concern".
North Korea has built a new two-storey uranium enrichment facility, the head of the world's nuclear watchdog said this week, calling it a cause for "serious concern".
The new building is part of the main Yongbyon nuclear complex, and reportedly capable of housing up to 28 centrifuge cascades used to enrich uranium.
In a report published late last month, the International Atomic Energy Agency said Pyongyang has also begun operating an expanded annex at another enrichment site.
"What makes North Korea's nuclear programme so concerning is that many of its facilities are unknown, concealed, and thus difficult to target," Edward Howell, a lecturer at the University of Oxford told the BBC.