Iran said on Thursday the United States has made extra demands and accused it of working to "complicate" efforts to restore a 2015 nuclear deal, after new Russian requests linked to the Ukraine war raised concerns of fresh delays.
Iran's supreme leader Ayatollah Ali Khamenei, who has the final say in major state policies, meanwhile, stressed his country will not give up on elements of "national strength", such as nuclear progress and regional influence.
Tehran is locked in negotiations with world powers to revive the nuclear deal that offered it sanctions relief in return for curbs on its atomic programme.
Its arch-foe the United States, under former president Donald Trump, unilaterally withdrew in 2018 from the accord known formally as the Joint Comprehensive Plan of Action.
