The UN's nuclear watchdog has confirmed that Iran has begun installing more advanced centrifuges used for enriching uranium -- Tehran's latest step in reducing its commitment to the 2015 nuclear deal with world powers.
The installed centrifuges were prepared for testing with uranium hexafluoride, or UF6, the feedstock for centrifuges, the International Atomic Energy Agency (IAEA) said in a statement on September 9.
The agency added that none of these machines were operating at the weekend.
Enriched uranium can be used to make fuel for reactors, but also nuclear weapons, and more advanced centrifuges could enable Iran to produce material for a potential nuclear bomb faster.
Tehran has always insisted that its nuclear ambitions are merely civilian.
Earlier this year, Iran breached the 300-kilogram limit on the amount of enriched uranium it is allowed to stockpile under the nuclear agreement, and began enriching uranium beyond the cap enshrined in the nuclear deal.
The moves came in response to sanctions the United States reinstated when Washington abandoned the so-called Joint Comprehensive Plan Of Action (JCPOA) between Iran and world powers including China, Britain, France, Germany, and Russia last year.
The sanctions have caused Iran's oil exports to collapse, the value of its currency to plummet, and its inflation rate to soar.
Iranian officials have insisted that the steps away from the agreement are reversible -- depending on other signatories offering economic relief.
U.S. President Donald Trump wants to force Iran to renegotiate the 2015 accord, arguing that the terms were not tough enough to prevent Iran from developing nuclear weapons, and agree to curbs to its ballistic-missile program.
Iranian officials have so far refused, saying they will not speak with the United States until the sanctions are eased.
IAEA acting Director-General Cornel Feruta, who returned from a weekend visit to Tehran, told the agency's board in Vienna on September 9 that inspectors continue "to verify and monitor Iran's nuclear-related commitments" under the deal.
He also said he emphasized to Iranian authorities "the importance of full and timely cooperation by Iran" and the need for Iran to "respond promptly to Agency questions related to the completeness of Iran’s safeguards declarations."