"There is progress in uranium enrichment, we have started mechanical tests of the IR-9 centrifuge with [an enrichment capacity] of 50 SWU," Kamalvandi told the state-run news agency ISNA.
Reports suggested earlier that Iran had begun to enrich uranium using the fourth cluster of advanced IR-2m centrifuges at the country's main nuclear facility.
Under the Joint Comprehensive Plan of Action (JCPOA), signed between Tehran and major global powers in 2015, Iran was allowed to enrich uranium only using first-generation IR-1 centrifuges at the underground fuel enrichment plant (FEP) at Natanz. Last year Iran began adding more advanced centrifuges that can enrich much faster than the IR-1.
These moves are part of Tehran's response to the US withdrawal from the deal, initiated by former US President Donald Trump, and the reimposition of sanctions against the country.