Iran has started producing enriched uranium at 60% purity at its underground Fordo nuclear plant, according to official media.
The country is already enriching to 60% purity at its Natanz nuclear facility, meaning that supplies of the radioactive metal held in at least two facilities are now closer to weapons-grade 90% purity.
The semi-official news agency IRNA reported: “In a letter to the International Atomic Energy Agency (IAEA), Iran has informed the agency that it has started enriching uranium to 60% purity at Fordo site using IR-6 advanced centrifuges.”
It added that the change at Fordo, about 62 miles south of Tehran, is a response to a resolution by the United Nations’ nuclear watchdog.
Last week, the International Atomic Energy Agency’s 35-nation board of governors passed a resolution ordering Iran to cooperate with its investigation into uranium traces found at three undeclared sites.
Iran dismissed the resolution – the second this year targeting Iran over the IAEA investigation – as “politically motivated”.
Iran’s nuclear chief Mohammed Eslami told Iranian media: “We had said that Iran will seriously react to any resolution and political pressure… that is why Iran has started enriching uranium to 60% purity from Monday at the Fordo site.”
It has been nearly two years since IAEA officials have had full access to Iran’s nuclear sites, and five months since surveillance equipment was removed.
This has become a big obstacle to talks on reviving the 2015 Iran nuclear deal, which have been stalled since September.
The deal – formally known as the Joint Comprehensive Plan of Action, or JCPOA – had eased sanctions on Iran in exchange for curbs on its nuclear programme.
But it fell apart after the US pulled out under Donald Trump’s presidency in 2018.
The US then re-imposed sanctions, and Tehran backed away from its part of the deal in response.
Before the deal, Iran’s uranium enrichment had been at 20% purity. The deal capped it at 3.67%.
Earlier this month, the IAEA said Iran has increased its stockpile of highly-enriched uranium and in a report, the body’s director Rafael Grossi said he was “seriously concerned” that Iran had still not engaged with the investigation into its nuclear activities.
US secretary of state Antony Blinken said on Tuesday he could not whether Iran has begun refining uranium to 60% at the Fordo site.