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 the body's spokesman Behrouz Kamalvandi as saying in a news conference here.
A total of 20 such centrifuges are now operational, he said, adding that Iran had the right to reduce its commitments to the nuclear deal since other signatories were not upholding their end of the deal.
"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.
The International Atomic Energy Agency (IAEA) will continue to monitor the Iranian programme and it has already been notified of the new measures, Kamalvandi said.
Part of the nuclear deal required the Islamic Republic to reduce its centrifuges by two thirds and use only its first-generation apparatus in exchange of slight easing of international sanctions.
"It is not a violation to the deal, it is a rectification," Kamalvandi said, warning Europe it was running out of time to react.
Meanwhile, US Defence Secretary Mark Esper said he was "not surprised" by the measures taken by Iran.
"I'm not surprised that Iran has announced that it is going to violate the JCPOA," he told a press conference in Paris, referring to the nuclear deal by its official name, the Joint Comprehensive Plan of Action.
"They had been violating it, they had violated the nuclear non-proliferation treaty for many years."
Iran's government has called on European members of the pact to facilitate its oil exportations or grant it a credit line to compensate Tehran for the sanctions imposed by Washington after President Donald Trump pulled out of the deal in 2018.
French President Emmanuel Macron has led diplomatic efforts to sit Trump down with Iranian President Hassan Rouhani.
The remaining members of the 2015 deal are Russia, China, France, the UK and Germany.
Iran, in response to the US move, started to enrich uranium at 4.5 per cent, more than the 3.67 per cent stipulated by the deal and began to exceed its permitted reserves of enriched uranium, which were set at 300 kg.
Despite increasing its nuclear activities, Iran continues to allow and cooperate with inspectors, IAEA reported. The agency's Director-General Cornel Feruta will visit Iran on Sunday, coinciding with the new measures taken by the Islamic Republic.
Furthermore, tensions between the US and Iran in the Strait of Hormuz a crucial thoroughfare in the Persian Gulf for the global oil sector have flared up.
( With inputs from IANS )