DUBAI (Reuters) - Iran will review its cooperation with the United Nations’ nuclear watchdog should it face “unjust” measures, Iranian parliament speaker Ali Larijani said, after EU powers last week triggered a dispute mechanism under Tehran’s 2015 nuclear deal.

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The move by France, Britain and Germany amounts to formally accusing Iran of violating the terms of the deal and could lead eventually to reimposing U.N. sanctions that were lifted under the pact.

“We state openly that if the European powers, for any reason, adopt an unfair approach in using the dispute mechanism, we will seriously reconsider our cooperation with the International Atomic Energy Agency,” state TV quoted Larijani as saying.

Tehran has continued to gradually roll back its nuclear commitments under the pact in reaction to sanctions reimposed by Washington since the U.S. quit the nuclear deal in 2018.

Tehran said last week it would abandon limits on enriching uranium, though it would continue to cooperate with the U.N. nuclear watchdog (IAEA), which is policing the nuclear pact.

President Hassan Rouhani, architect of the nuclear deal, has repeatedly said that Tehran’s nuclear steps were reversible if Tehran’s economy was shielded by other parties to the deal from U.S. penalties.

Under the deal between Iran and major powers, Tehran agreed to curb its nuclear program in exchange for lifting international sanctions against the Islamic Republic.

The three European nations said they still wanted the 2015 nuclear deal to succeed and were not joining a “maximum pressure” campaign by the United States.

The mechanism involves a Joint Commission, whose members are Iran, Russia, China, Germany, France, Britain and the European Union, seeking to resolve the dispute.

A group of Iranian lawmakers signed a statement on Sunday warning the European powers to “stop their hostile approach” toward Tehran, Iran’s semi-official Tasnim news agency reported.

“Otherwise we, as representatives of the Iranian nation, will decide whether Iran should remain in the nuclear deal or whether it should continue its cooperation with the IAEA,” the lawmakers said.

Iran’s Supreme Leader Ayatollah Ali Khamenei, not parliament, has the last say on state matters such as Tehran’s nuclear standoff with the West.

The Tasnim report did not say how many lawmakers signed the statement, which also called on the government to consider downgrading its diplomatic ties with Britain after Iranian officials accused the U.K envoy to Tehran of attending an illegal protest, which he denies.