Iran said on Wednesday it would begin developing centrifuges to speed up the enrichment of uranium, which can produce fuel for power plants or for atomic bombs.
Iran said on Friday it had taken a step to further downgrade its commitments to a 2015 nuclear deal with the world's most powerful nations, according to Iranian media, in retaliation to US sanctions reimposed on Tehran.
Iran said on Wednesday it would begin developing centrifuges to speed up the enrichment of uranium, which can produce fuel for power plants or for atomic bombs. Tehran denies seeking nuclear weapons.
"Foreign Minister (Mohammad Javad) Zarif, in a letter to EU (European Union) policy chief (Federica Mogherini) announced that Iran has lifted all limitations on its (nuclear) Research and Development (R&D) activities," Iran's Students News Agency ISNA quoted Foreign Ministry spokesman Abbas Mousavi as saying.
Under the deal, Iran is allowed limited research and development on advanced centrifuges, which accelerate the production of fissile material that can be used to make a nuclear bomb. Iran also agreed to limitations on specific research and development activities for eight years.
President Donald Trump pulled the United States out of the deal last year, arguing it did not go far enough, and reimposed sanctions that has slashed Iran's crude oil sales by more than 80 per cent.
Iran has responded by scaling back its nuclear commitments since May and has threatened to continue removing restraints on its nuclear programme unless European parties to the pact did more to shield Iran's economy from the US penalties.
Britain and France, both parties to the pact, have called on Iran to refrain from any concrete action that does not comply with the agreement.
State TV said Iran's Atomic Energy Organisation would unveil on Saturday details of Tehran's new step, which President Hassan Rouhani will accelerate Iran's nuclear programme.
Iran has said that it still aims to save the agreement and on Wednesday gave Europe a new 60-day deadline to salvage the pact, reached under former US President Barack Obama, which curbed Iran's nuclear work in exchange for the lifting of most sanctions in 2016.
Iran's new measures will be "peaceful, under surveillance of the UN nuclear watchdog and reversible" if European powers keep their promises, President Hassan Rouhani said on Wednesday.