As a third step in Iran's reduction of commitments under the deal, the Atomic Energy Organization of Iran (AEOI) activated 20 IR-4 and 20 IR-6 centrifuges, Press TV quoted AEOI spokesman Behrouz Kamalvandi as saying in a news conference here.
"We have started lifting limitations on our Research and Development imposed by the deal, it will include development of more rapid and advanced centrifuges.
"All these steps are reversible if the other side fulfils its promises," he added.
Kamalvandi said the International Atomic Energy Agency (IAEA) has been informed about Iran's new nuclear steps which it will continue to monitor.
Saturday's announcement comes a day after Iran officially informed the European Union (EU) that it will begin unlimited nuclear research and development (R&D) work.
Foreign Minister Mohammad Javad Zarif told EU foreign policy chief Federica Mogherini that Iran was further scaling back its commitments under the Joint Comprehensive Plan of Action (JCPOA) due to the inability of its three European signatories the UK, France and Germany to meet their end of the bargain, Press TV reported.
In a statement, Foreign Ministry spokesman Abbas Mousavi said the third step was Tehran's response to "widespread and continued violations" of the nuclear deal ever since the US dropped out of it 16 months ago in May 2018.
Iran had announced the first stage of its countermeasures in May by increasing its enriched uranium stockpile to beyond the 300 kg cap set by the agreement.
It took the second step two months later, when it started to enrich uranium to purity rates beyond the JCPOA limit of 3.76 per cent.
( With inputs from IANS )