TEHRAN, Sept. 9 (Xinhua) -- Iran has announced its third step to suspend parts of its commitments to the landmark 2015 nuclear accord, known as Joint Comprehensive Plan of Action (JCPOA), in response to the latest U.S. sanctions on Tehran and Europe's sluggishness to save the deal.

An Iranian expert said that any signal from the Iranian side for talks with the United States under the current circumstances would show disadvantage toward Iran.

"Whenever Iran speaks of negotiations with the United States, it creates an artificial respiration for (U.S. President Donald) Trump's team, and the Americans think that their political pressure on Iran has been effective," Foad Izadi, expert of international issues, said in an interview.

Izadi, also a professor at the University of Tehran, believed that any bilateral negotiations will be for the advantage of the U.S. administration.

"The Americans are gaining more privileges through negotiations with Iran, and we should take the next steps (to reduce nuclear commitments) earnestly to counter their attitudes," Izadi added.

On Sept. 7, Iran announced that it has activated 20 IR-4 centrifuges and 20 advanced IR-6 centrifuges to boost the country's stockpile of enriched uranium.

Iranian President Hassan Rouhani said that with the recent removal of limitations on Iran's nuclear program, "we will witness research and development on different kinds of centrifuges, including new ones and also whatever is needed to enrich uranium in an accelerated way."

Meanwhile, he stressed that the nuclear activities of Iran would remain peaceful and will be supervised by the International Atomic Energy Agency.

Rouhani also said that Iran would give Europeans two months to fulfil their commitments to shield the Iranian economy from the U.S. sanctions.

Since May, Iran has made two other moves to scale back its obligations under the JCPOA to build stockpiles of nuclear fuel and enrich low-grade uranium to a higher level of purity.

The JCPOA was reached in July 2015 between Iran and the P5+1, namely the United States, Britain, France, Russia, China plus Germany, together with the European Union. In May 2018, the United States scrapped the pact.

Washington then imposed harsher sanctions on Iran's oil exports and other key industries, as well as on top officials and part of its military, the Islamic Revolution Guards Corps.

Furthermore, Iran is disappointed at Europe for the latter's proposed payment channel to facilitate trade between Europe and Iran.

Iran says the mechanism has not been able to "practically" offset the impact of U.S. sanctions on Iran's economy, not to mention the U.S. dismissal of French-led efforts to provide Tehran with a 15 billion-U.S. dollar economic lifeline.

At the G7 summit last week, French president said that he was "convinced that an agreement" could be found if the United States and Iranian presidents could meet.

On Sept. 6, U.S. Secretary of Defense Mark Esper said that there are indications that Iran is "inching" toward new talks with the United States.

Esper's remarks followed Trump's gestures on Sept. 4 that he would be willing to meet with Rouhani at the U.N. General Assembly in New York later this month.

"Sure, anything's possible. They would like to be able to solve their problem," Trump said, adding that "we could solve it (the problem) in 24 hours."

However, Rouhani ruled out any bilateral talks with the White House, retreating from his earlier remarks of openness to talk with anyone when the interests of his people are at stake.

Rouhani said that any negotiations with the United States would be possible within the framework of P5+1 and only after the United States lifts all sanctions against Iran.

"The issue of bilateral talks is not on the agenda in principle ... We have no plans for bilateral talks with the U.S. and have never had," he added.

"There have been a lot of offers for talks but our answer will always be negative," Rouhani said.

On the eve of the U.S. 2020 presidential elections, Trump needs "an Iran agreement" since he has had no achievement in the U.S. foreign policy, Izadi pointed out, adding that Trump's exit from the deal will have no achievement for the United States.