“The Agency today (17 April) verified that Iran had begun the production of UF6 enriched up to 60% by feeding UF6 enriched up to 5% into the two cascades of IR-4 and IR-6 centrifuges in R&D lines. According to Iran’s declaration to the Agency, the enrichment level was 55.3%,” Gharibabadi tweeted.

On Friday, Iran's nuclear chief Ali Akbar Salehi said on Friday that Iran had begun enriching uranium at 60 percent at the Natanz nuclear facility.