Iran has pulled out of key commitments under the 2015 International Nuclear Deal, a year after it was abandoned by the US.
President Hassan Rouhani said Iran will keep enriched uranium stocks in the country and not sell them abroad.
He also threatened to resume production of higher enriched uranium in 60 days.
The accord is aimed at curbing Iran’s nuclear ambitions in return for sanctions relief, but Iran-US tensions have risen since the US quit.
The landmark nuclear deal agreed by Iran and the five permanent members of the UN security council – the US, UK, France, China and Russia – plus Germany – was thrown into flux when President Trump announced the US withdrawal one year ago.
European backers of the deal, who oppose reinstating sanctions, have been trying to find ways to salvage it.