Iran has breached the limit on its stockpile of enriched uranium set under a 2015 nuclear deal with world powers, the global watchdog has confirmed.
The International Atomic Energy Agency said its inspectors had verified the 300kg (660lb) cap had been exceeded.
Iran stepped up production of enriched uranium, which is used to make reactor fuel and potentially nuclear weapons, in response to reinstated US sanctions.
European nations have warned that any violation will bring consequences.
The deal allows for the re-imposition of multilateral sanctions that were lifted in return for Iran limiting its nuclear activities.
What has Iran said?
“Based on what I have been told, Iran has exceeded the 300kg limit in accordance with its plan,” Iranian Foreign Minister Mohammad Javad Zarif was quoted by Isna news agency as telling reporters in Tehran on Monday afternoon.
“We have clearly said what we will do and we will act accordingly. We deem it as part of our rights under the Joint Comprehensive Plan of Action,” he added, referring to the official name of the nuclear deal.
An IAEA spokesperson later told the BBC: “We can confirm that IAEA Director General Yukiya Amano has informed the Board of Governors that the agency verified on 1 July that Iran’s total enriched uranium stockpile exceeded 300kg of UF6 [uranium hexafluoride]enriched up to 3.67% U-235 (or the equivalent in different chemical forms).”
The Iranian foreign ministry’s spokesman meanwhile warned that Iran still planned to suspend other commitments under the deal in 10 days unless European powers took “practical and tangible steps” to implement their new mechanism for facilitating trade and shield the Iranian economy from the effects of the US sanctions.
The mechanism, known as Instex, essentially allows goods to be bartered between Iranian and foreign companies without direct financial transactions. It became operational on Saturday, but Mr Zarif said it did not meet Iran’s needs.
The development comes at a time of high tension in the Middle East, with Iran shooting down a US drone over the Strait of Hormuz in disputed circumstances, and the US accusing Iran of being behind two sets of attacks on oil tankers.