Iran has increased enriched uranium by 50%, says UN watchdog

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Iran has increased its stockpile of highly enriched uranium by 50 per cent, according to the UN’s nuclear watchdog, raising the stakes even as the country holds talks with the US to resolve its nuclear stand-off with the west.

According to a confidential International Atomic Energy Agency report obtained by the Financial Times, as of May 17, Iran possessed 408.6kg of uranium enriched to 60 per cent purity. This marks a sharp rise of 133.8kg since February.

Iran remains the only non-nuclear weapons state known to have uranium enriched to such a high degree — a development the IAEA called “a matter of serious concern” due to the significant risks of nuclear proliferation. Uranium enriched to 60 per cent is just below weapons-grade, generally defined at 90 per cent enrichment.

This escalation comes amid indirect nuclear talks between Iran and the US, facilitated by Oman and which began in April. Despite five rounds of negotiations, the two sides remain deeply divided over Iran’s uranium enrichment programme.

The Trump administration insists Iran must halt all uranium enrichment before sanctions are lifted, while Tehran maintains its enrichment programme is a sovereign right, describing any rollback as a “red line” it will not cross.

Analysts warn the increased uranium stockpile raises the stakes for both diplomacy and adds to the sense of urgency on the need for a deal resolve the crisis.

Kelsey Davenport of the Arms Control Association said: “If the [IAEA] board adopts a resolution, Iran is likely to retaliate, putting at risk the progress Tehran and Washington are making at the negotiating table.”

She added that a comprehensive nuclear deal offers the best path to resolving the IAEA’s concerns. “Both the United States and Iran should exercise restraint in response to the IAEA report and remain focused on reaching a deal.”

In the latest diplomatic effort, Oman’s Foreign Minister Badr bin Hamad al-Busaidi visited Tehran on Saturday to deliver “elements of a US proposal”, according to Iran’s Foreign Minister Abbas Araghchi, who said Tehran will respond “appropriately”.

Iran insists its nuclear programme is peaceful and compliant with religious prohibitions against nuclear weapons.

But it now has the capacity to produce sufficient fissile material required for nuclear weapons in less than two weeks, experts say.

The IAEA report also reiterated long-standing concerns over Iran’s lack of transparency. Inspectors say Tehran has failed to provide credible explanations for undeclared nuclear materials found at three sites that are part of a long running probe by the watchdog, making it impossible to verify whether the material was consumed, mixed or remains outside international safeguards.

Iran’s foreign ministry dismissed the Vienna-based agency’s report as politically motivated, accusing the US, Britain, France, and Germany of pushing for a “repetitive, unfair” narrative.

But the unresolved issues highlight the fragile state of current diplomacy. The coming months are critical as Iran faces potential military threats — particularly from Israel — and the looming possibility of renewed UN sanctions.

European powers have warned they may trigger the “snapback” mechanism to reinstate sanctions by October if Iran does not comply with nuclear restrictions, a move that could sharply escalate tensions.

US President Donald Trump has said that he prefers a diplomatic solution to the crisis but has warned of military action if he is unable to get a deal.

Ali Vaez, a senior Iran analyst at the International Crisis Group, cautioned that without meaningful progress soon, negotiations risk collapse, leading to a more hostile stand-off in Vienna and New York.

“The agency’s reporting confirms Iranian obfuscation over its past undeclared work and escalation in its current nuclear activity,” Vaez said.

“Unless the US and Iran are able to make headway in their negotiations, diplomatic efforts that have thus far been focused on Muscat and Rome are likely to shift into an even more contentious and high-stakes stand-off.”