A fire has reportedly damaged a building at a nuclear facility in Iran.
Atomic Energy Organisation of Iran (AEOI) spokesman Behruz Kamalvandi said there was an incident in “one of the industrial sheds under construction” at the Natanz uranium enrichment plant.
There were no fatalities or concerns about contamination, he added.
The AEOI later published a photo showing a partly burned building, which US-based analysts identified as a new centrifuge assembly workshop.
Centrifuges are needed to produce enriched uranium, which can be used to make reactor fuel but also nuclear weapons.
Meanwhile, in a statement sent to BBC Persian journalists before the AEOI’s announcement, an unknown group calling itself “Cheetahs of the Homeland” claimed it had attacked the building. The group said its members were part of “underground opposition with Iran’s security apparatus”.
The claim could not immediately be verified by the BBC.
The International Atomic Energy Agency (IAEA), which monitors Iran’s compliance with a 2015 nuclear deal struck with world powers, said it was aware of the reports from Natanz and currently anticipated no impact on its verification activities.
The incident comes six days after an explosion near the Parchin military complex.
The Iranian authorities said the blast was caused by “leaking gas tanks” at the site, but analysts said satellite photographs showed it happened at a nearby missile production facility.
Parchin is where Western powers suspect Iran carried out tests related to nuclear warhead detonations more than a decade ago. Iran insists its nuclear programme is peaceful and denies that it sought to develop nuclear weapons.