Iran has begun feeding uranium hexafluoride (UF6) gas feedstock into the advanced IR-2m uranium-enriching centrifuges installed at its underground plant at Natanz, a U.N. nuclear watchdog report obtained by Reuters on Wednesday said.

The move is the latest breach by Iran of its nuclear deal with major powers, which says it can only accumulate enriched uranium with first-generation IR-1 machines and those are the only ones it can operate at the underground plant. A previous IAEA report said Iran had installed IR-2m machines underground.

“On 14 November 2020, the Agency verified that Iran began feeding UF6 into the recently installed cascade of 174 IR-2m centrifuges at the Fuel Enrichment Plant (FEP) in Natanz,” the International Atomic Energy Agency report to member states dated Tuesday said.