Iran has begun operating advanced centrifuges at an underground section of its primary nuclear enrichment facility, the UN's nuclear watchdog said Wednesday (November 18th).
The International Atomic Energy Agency (IAEA) had reported last week that Iran had installed the centrifuges in a buried part of the Natanz nuclear complex.
IAEA director-general Rafael Grossi said Wednesday that while at the time of that report "they had not started operations... it is now happening".
Under the terms of Iran's 2015 deal with world powers, it is only meant to enrich uranium with a less sophisticated variety of centrifuges.
Since May of 2019, however, Iran has taken steps to violate that limit and several others laid down in the deal.
Grossi said the operation of the centrifuges in question did not mean there would be any "significant increase in the volumes" of uranium being enriched, since they been transferred from a different part of the facility.
In its report last week the IAEA said that Iran's stockpile of enriched uranium now stood at over 12 times the limit in the 2015 accord.
In July an above-ground part of the Natanz facility was damaged in an explosion which Iran blamed on "sabotage".
Grossi also addressed another part of last week's report in which the IAEA said Iran's explanations over the presence of nuclear material at an undeclared site in the country were "not credible".
He named the site as being in the Turquzabad district of Tehran.
"What they are telling us, from a technical point of view, does not add up," Grossi said.
"This is not an academic exercise. They need to explain why we found what we found," he added.