The US has sent Iran a proposal for a nuclear deal between Tehran and Washington, the White House confirmed on Saturday.

Iranian Foreign Minister Abbas Araghchi said he had been presented with “elements of a US deal” by his Omani counterpart Badr Albusaidi during a short visit to the Iranian capital.

It comes after a report by the UN nuclear watchdog said Iran had further stepped up its production of enriched uranium, a key component in the making of nuclear weapons.

White House press secretary Karoline Leavitt said on Saturday it was in Tehran’s “best interest to accept” the deal, adding: “President Trump has made it clear that Iran can never obtain a nuclear bomb”.

Leavitt said a “detailed and acceptable” proposal had been sent to Iran by US President Donald Trump’s special envoy Steve Witkoff.

The US proposal “will be appropriately responded to in line with the principles, national interests and rights of the people of Iran”, Araghchi wrote on X.

The precise details of the deal are not yet clear.

The proposal follows a report by the International Atomic Energy Agency (IAEA) – seen by the BBC – which found Iran now possesses over 400kg of uranium enriched to 60% purity – close to the 90% purity required for weapons-grade uranium.

This is well above the level of purity sufficient for civilian nuclear power and research purposes.

It is enough for about 10 nuclear weapons if further refined, making Iran the only non nuclear-armed state producing uranium at this level.

The report paves the way for the US, Britain, France and Germany to push for the IAEA’s board of governors to find Iran in violation of its non-proliferation obligations.

Iran insists its programme is peaceful. On Saturday, Iranian state media described the IAEA report as “politically motivated” containing “baseless accusations”.

Iran has said it will “implement appropriate measures” in response to any effort to take action against Tehran at the IAEA governors’ meeting.

The US has long sought to limit Iran’s nuclear capacity. Talks between the two powers mediated by Oman have been under way since April.

Both sides have expressed optimism during the course of the talks but remain divided over key issues – chief among them, whether Iran can continue enrichment under any future agreement.

Despite the ongoing negotiations between Tehran and Washington, the IAEA report offered no indication that Iran has slowed its nuclear enrichment efforts.

Iran has produced highly enriched uranium at a rate equivalent to roughly one nuclear weapon per month over the past three months, the IAEA report found.

US officials estimate that, if Iran chooses to make a weapon, it could produce weapons-grade material in less than two weeks and potentially build a bomb within months.

Iran has long denied it is attempting to develop nuclear weapons. However, the IAEA said it could not confirm whether this was still the case because Iran refuses to grant access to senior inspectors and has not answered longstanding questions about its nuclear history.

Trump is seeking a new nuclear agreement with Tehran after pulling the US out of a previous nuclear agreement between Iran and six world powers in 2018.

This nuclear deal, known as the Joint Comprehensive Plan of Action or JCPOA, was signed in 2015 by Iran and the US, China, France, Russia, Germany and the UK.

The JCPOA sought to limit and monitor Iran’s nuclear programme in return for lifting sanctions that had been placed on the regime in 2010 over suspicions that its nuclear programme was being used to develop a bomb.

But Donald Trump withdrew from the deal during his first term in office, claiming JCPOA was a “bad deal” because it was not permanent and did not address Iran’s ballistic missile programme, amongst other things.

Trump then re-imposed US sanctions as part of a “maximum pressure” campaign to compel Iran to negotiate a new and expanded agreement.

In the intervening years, Tehran has steadily overstepped the 2015 agreement’s limits on its nuclear programme, designed to make it harder to develop an atomic bomb.

Trump has previously threatened to bomb Iran’s nuclear facilities if diplomacy fails to achieve a deal. (BBC)