Iran has stockpiled 12 times the amount of enriched uranium permitted under a 2015 nuclear deal with world powers, a global watchdog has said.
The International Atomic Energy Agency (IAEA) said Iran’s stockpile of low-enriched uranium had reached 2,442.9kg this month.
Iran insists its nuclear programme is exclusively for peaceful purposes.
The IAEA also said Iran’s explanation for the presence of nuclear material at an undeclared site was “not credible”.
On Twitter, the country’s ambassador to the IAEA, Gharib Abadi, said “any hasty comments should be avoided”, adding: “Interactions are ongoing with a view to finalize the resolution of the matter.”
In its latest report, distributed to member states, the IAEA did not identify the site where it had found nuclear material. An unnamed source told AFP news agency that there was no indication it had been used for processing uranium, but it could have been used to store the material.
The IAEA added that Iran was continuing to enrich uranium to a purity of up to 4.5% – in violation of the 3.67% threshold agreed under the 2015 deal.
The watchdog is still analysing samples taken in September from two suspected former nuclear sites, which were opened up to inspectors this year.
Under a nuclear agreement signed with China, France, Germany, Russia, the UK and the US, Iran is allowed to produce up to 300kg of enriched uranium in a particular compound form (UF6), which is the equivalent of 202.8kg of uranium. But after US President Donald Trump abandoned the nuclear accord and reinstated crippling economic sanctions, Iran began to build its stockpile.
Low-enriched uranium can be used to produce fuel for power plants. Weapons-grade uranium is 90% enriched or more.