TEHRAN – Behrooz Kamalvandi, spokesman for the Atomic Energy Organization of Iran, has said that a team of Russian specialists will visit the Fordow nuclear facility on Sunday as part of a project on stable isotopes.

Tehran and Moscow reached a deal on stable isotopes about a year ago, Kamalvandi said on Thursday, adding that different Iranian delegates have traveled to Russia and Russian experts have visited Iran since then.

“Today, we are at the stage of installing some equipment and Russian experts will arrive in Iran on Sunday to begin the installation work,” he told IRNA.

The project will probably begin on Sunday or the following day, he added.

Earlier on Thursday, the AP quoted Russia’s RIA Novosti news agency as saying that Russian technical specialists were set to arrive this week at the Fordow nuclear facility.

Director General of the International Atomic Energy Agency (IAEA) Yukiya Amano said in January 2016 that Iran had removed “excess centrifuges and infrastructure” from the Fordow enrichment facility in line with its commitments under the 2015 nuclear agreement, also known as the Joint Comprehensive Plan of Action (JCPOA).

Amano made the remark in a statement issued on the first anniversary of the implementation of the JCPOA, which was signed between Iran and six world powers including the U.S., Russia, Britain, France, China and Germany.

The deal was reached in July 2015 and went into effect in January 2016.

Under the accord, Iran undertook to apply certain limits to its nuclear program in exchange for the termination of all nuclear-related sanctions that had been imposed against Tehran.

The IAEA, which is the official institution to verify Iranian compliance, has consistently confirmed the Islamic Republic’s commitment to its contractual obligations.

However, U.S. President Donald Trump strongly opposes the JCPOA – which was negotiated by his predecessor, Barack Obama – and warned that he might ultimately “terminate” it.

Last month, Trump extended waivers of key economic sanctions on Iran, lifted under the nuclear agreement, for another 120 days but said he was doing so “for the last time.”

He further called on European allies and the U.S. Congress to work with him to fix what he called “disastrous flaws” in the pact or face a U.S. exit.

Iranian officials have repeatedly dismissed U.S. calls for renegotiations, saying the JCPOA is not renegotiable.

“Trump’s policy & today’s announcement amount to desperate attempts to undermine a solid multilateral agreement, maliciously violating its paras 26, 28 & 29. JCPOA is not renegotiable: rather than repeating tired rhetoric, U.S. must bring itself into full compliance -just like Iran,” Foreign Minister Mohammad Javad Zarif tweeted on January 12.