PARIS: The European countries party to the Iran nuclear deal told Tehran on Wednesday its decision to enrich uranium at 60% purity, bringing the fissile material closer to bomb-grade, was contrary to efforts to revive the 2015 accord.
But in an apparent signal to Iran's arch-adversary Israel, which Tehran blamed for an explosion at its key nuclear site on Sunday, European powers Germany, France and Britain added that they rejected "all escalatory measures by any actor".
Israel, which the Islamic Republic does not recognise, has not formally commented on the incident at Iran's Natanz site, which appeared the latest twist in a long-running covert war.
The nuclear deal has unravelled as Iran has breached its limits on uranium enrichment in a graduated response to the US withdrawal from it in 2018 and Washington's reinstatement of harsh economic sanctions against the Islamic Republic.
Last week, Iran and fellow signatories held what they described as "constructive" talks to restore the deal ditched by ex-president Donald Trump's administration - which saw the terms as too lenient on Tehran - in a move welcomed by Israel.
The United States and Iran will reconvene indirect talks on Thursday in Vienna, White House press secretary Jen Psaki said.
But Britain, France and Germany said Tehran's new decision to enrich at 60 percent, and activate 1,000 advanced centrifuge machines at its Natanz plant, was at odds with the talks, not based on credible civilian reasons and constituted an important step towards the production of a nuclear weapon.
"Iran's announcements are particularly regrettable given they come at a time when all JCPoA (Joint Comprehensive Plan of Action) participants and the United States have started substantive discussions, with the objective of finding a rapid diplomatic solution to revitalise and restore the JCPoA," the three countries said in a statement, referring to the 2015 deal.
"Iran’s dangerous recent communication is contrary to the constructive spirit and good faith of these discussions," it said of the talks, which resume between Iran and global powers in Vienna on Thursday, aimed at salvaging the accord.
In an apparent rebuff later on Wednesday, Iranian Supreme Leader Ayatollah Ali Khamenei said the United States was trying to impose its terms for rescuing the deal and European powers were doing Washington's bidding.
"America does not seek to accept the truth in negotiations ... Its goal in talks is to impose its own wrong wishes ... European parties to the deal follow America's policies in talks despite acknowledging Iran’s rights," Khamenei, who has the last word on Iranian matters of state, was quoted as saying by state television.
"The nuclear talks in Vienna must not become talks of attrition...This is harmful for our country."