Iran's President Hassan Rouhani has unveiled the country's newest advanced nuclear centrifuge in a ceremony to mark the National Nuclear Technology Day.
The move is being seen by some countries as an open breach of the nuclear deal.
Th inauguration of the IR-9 comes as the five world powers remaining in the 2015 nuclear deal (China, France, Russia, the United Kingdom and Germany) try to bring the U.S. back into the agreement.
In a ceremony at Iran's Natanz uranium enrichment plant in Isfahan province, President Rouhani said: "Please start the process of feeding uranium to the new generation of centrifuges at the Natanz enrichment complex."
The Iranian leader unveiled three cascades of 164 IR-6 centrifuges, 30 IR-5 and another 30 IR-6 devices.
The move to step up enrichment comes after talks between the remaining parties to the Iran nuclear deal met in Vienna on Tuesday.
Then-president Donald Trump withdrew from the deal in 2018 but his successor Joe Biden has said he is ready to return, arguing the deal had been successful in dramatically scaling back Iran's nuclear activities.