Supreme Leader Ayatollah Ali Khamenei said on Monday Iran might enrich uranium up to 60% purity if the country needed it and would never yield to U.S. pressure over its nuclear activity, state television reported.
Iran's 2015 nuclear deal with six powers, which it has been breaching since the United States withdrew in 2018, caps the fissile purity to which Iran can refine uranium at 3.67%, well under the 20% achieved before the agreement and far below the 90% suitable for a nuclear weapon.
"Iran's uranium enrichment level will not be limited to 20%. We will increase it to whatever level the country needs...We may increase it to 60%," the TV quoted Khamenei as saying, upping the ante in a stand-off with Washington over the future of the fraying deal.
"Americans and the European parties to the deal have used unjust language against Iran...Iran will not yield to pressure. Our stance will not change," Khamenei said.
He repeated a denial that Iran would ever seek to build nuclear weapons.
U.S. President Joe Biden’s administration said last week it was ready to talk to Iran about both nations returning to the accord abandoned by Biden's predecessor Donald Trump.
Secretary of State Antony Blinken said on Monday Washington would aim to bolster and extend the 2015 pact, which aimed to limit Iran's enrichment potential - a possible pathway to atomic bombs - in exchange for a lifting of most sanctions.
Iran and the United States have been at loggerheads over who should take the first step to revive the accord.
Although under domestic pressure to ease economic hardships worsened by sanctions, Iranian leaders insist Washington must end the economic pressure campaign first to restore the deal, while Washington says Tehran must first return to compliance.
Khamenei added that the Islamic Republic had never pursued the construction or use of nuclear weapons as this was forbidden by its religion.
"If we wanted to..., no one could stop Tehran from acquiring nuclear weapons..., (but) Iran is not seeking nuclear weapons," he said.
Blinken, addressing the Conference on Disarmament in Geneva, said in a pre-recorded speech: "The United States remains committed to ensuring that Iran never acquires a nuclear weapon. Diplomacy is the best path to achieve that goal."
Biden has said that if Iran came back into "strict compliance" with the 2015 pact, his administration would do the same, according to Blinken.
"Working with allies and partners, we will also seek to lengthen and strengthen the JCPOA (Joint Comprehensive Plan of Action, or nuclear deal) and address other areas of concern, including Iran's destabilizing regional behavior and ballistic missile development and proliferation," Blinken said.