The statement of Larijani was a reaction to the launch of the dispute settlement mechanism in the framework of Iranian nuclear program, which was implemented by the United Kingdom, France and Germany on January 14.
"We openly declare that if European states for any reason take an unfair approach to the use of the dispute settlement mechanism, we will seriously review our cooperation with the International Atomic Energy Agency," said the speaker of the Iranian parliament.
Earlier German Chancellor Angela Merkel said that Germany is interested in maintaining the Iranian nuclear deal and will make diplomatic efforts for this.
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.