Diplomatically isolated North Korea is believed to operate multiple facilities for enriching uranium, a key step in making nuclear warheads, South Korea's spy agency has said. That includes one at the Yongbyon nuclear site, which Pyongyang purportedly decommissioned after talks but later reactivated in 2021. "In our periodic assessments, we have been able to confirm that there's a rapid increase in the operations" of the Yongbyon reactor, International Atomic Energy Agency (IAEA) chief Rafael Grossi said in Seoul, where he met South Korea's foreign minister. The agency also observed a rise in operations at Yongbyon's reprocessing unit and light-water reactor, as well as the activation of other facilities, Grossi told reporters. "All that points to a very serious increase in the capabilities of (the) DPRK in the area of nuclear weapons production, which is estimated at a few dozen warheads", he said, referring to the Democratic People's Republic of Korea, the North's official name. North Korea, which conducted its first nuclear test in 2006, is under rafts of UN sanctions for its banned weapons programmes. It has declared that it will never surrender its nuclear weapons, and cut off access to IAEA inspectors in 2009. The agency has noted the construction of a "new facility similar to the enrichment facility in Yongbyon", Grossi said. It was "not easy to calculate" any production increases without visiting the site. (Bssnews)