Iran has transported a first cascade of advanced IR-2m centrifuges from an above-ground facility at Natanz to an underground plant at the site, according to a report by the International Atomic Energy Agency (IAEA). The transfer violates the Joint Comprehensive Plan of Action (JCPOA), which limits Iran to operating only first-generation IR-1 centrifuges in the underground portion of Natanz. The cascade is installed and connected but has not been fed with uranium hexafluoride gas. Iran has also begun installing a cascade of IR-4 centrifuges, and plans to install a cascade of IR-6 centrifuges in the underground plant.