A report by the UN's nuclear watchdog says Iran is starting to operate a new workshop at its Natanz nuclear facility that will make parts for uranium-enriching centrifuges with machines recently moved there from its Karaj facility.
"On April 12, the agency completed the installation of the surveillance cameras at this location and then removed the seals from the machines," Reuters quoted the confidential report to member states from the International Atomic Energy Agency as saying, without describing where at Natanz that location was.
"On April 13, Iran informed the agency that the machines would start operating at the new workshop the same day," it added, without saying whether it had verified that the machines had started operating.
The development comes as Iran and several global powers negotiate a revival of the 2015 nuclear accord under which Tehran had significantly limited its sensitive nuclear activities in exchange for sanctions relief.
The United States withdrew from the accord in 2018 and reimposed tough sanctions that have crippled Iran's economy. Iran has responded by gradually expanding its nuclear work.
Under the administration of President Joe Biden, Washington has expressed an interest in rejoining the agreement if Iran returns to full compliance.
Several rounds of talks over the past year have brought the two sides close to an agreement, though the discussions recently stalled over several remaining issues.