An American official announces that Iran has abandoned some of the conditions for reviving the nuclear agreement

A senior US official says Iran has abandoned some basic conditions for reviving the nuclear deal aimed at curbing its nuclear programme.

A senior US official told Reuters that Iran has abandoned some key conditions for reviving the nuclear deal aimed at curbing its nuclear programme, including its insistence that International Atomic Energy Agency inspectors finish some investigations into its nuclear programme, raising the prospect of a deal.

The United States is preparing to respond soon to a draft agreement proposed by the European Union that would revive the 2015 nuclear deal with Iran that was abandoned by former President Donald Trump and which current President Joe Biden wants to revive.

The official, who spoke on condition of anonymity due to the sensitivity of the matter, added that although Tehran says Washington has to make some concessions, it has given up some of its basic demands.

"They came back last week and basically abandoned the main obstacles to a deal," he said.

"We believe they have finally made the difficult decision and moved toward potentially returning to the agreement on terms that President Biden can accept... If we are closer today, it is because Iran has moved. They have given up on the issues they have been holding on to since the beginning."

There was no immediate comment from the Iranian Foreign Ministry.

The official said Iran had already largely backtracked on its demand that the United States remove Iran's Revolutionary Guard from the list of foreign terrorist organizations.

He added: "We said that we would not do this under any circumstances. They continued to submit the request. A month ago they began to loosen their adherence to this basic request and said that you can keep the classification, but we would like to lift it from a number of companies affiliated with the Iranian Revolutionary Guards, so we said: No, we will not that".

Iran also wants to ensure that the International Atomic Energy Agency closes investigations into the effects of uranium of unknown origin.

"Iran wants guarantees that the International Atomic Energy Agency will close them all," the official said. "We said we would never accept that."

In June, the IAEA's Board of Governors overwhelmingly passed a resolution criticizing Iran for not providing an explanation for the effects of uranium at three undisclosed sites.

The official said that gaps remained between the United States and Iran and that "it may take a little longer" to reach a final agreement, if that is possible.

"We are studying Iran's response now and we will get back to them soon," the official said.

Earlier, US State Department spokesman Ned Price said there was no guarantee of an agreement, explaining that "the outcome of these ongoing discussions remains uncertain, with gaps remaining."

Washington will have to lift some sanctions under the terms of the deal, but US officials say a return to the deal is critical to preventing a nuclear crisis in the Middle East.

"If we do this deal, that means we have to lift some sanctions, but Iran has to dismantle its nuclear program," the official said.

The official added that all this comes at a time when Iran is believed to have enough enriched uranium, if purified, to make several weapons and is closer than ever to gaining the ability to produce such weapons.

The nuclear deal between Iran and world powers appeared poised to return in March after 11 months of indirect talks between the United States and Iran in Vienna.

But negotiations collapsed due to obstacles such as Iran's desire to remove the Revolutionary Guards from the list of terrorist organizations.

Iran has also demanded that the United States ensure that no future US president abandons the agreement. Biden cannot provide such assurances because the agreement is a political understanding rather than a legally binding treaty.

A second official said that after full implementation of the agreement, the IAEA would be able to resume a comprehensive inspection regime that would enable it to detect any Iranian attempt to secretly acquire a nuclear weapon. Many oversight mechanisms will remain in place indefinitely.

This official also said that Iran would be prevented from enriching and storing uranium above very limited levels, depriving it of the materials needed to make a bomb.

The official added that Iran would not be allowed to possess any enriched uranium with a purity of 20 and 60 percent such as what it is storing now, and the advanced centrifuges that Tehran operates will be stopped or removed, including all centrifuges in its fortified underground facilities in Fordow.

"The strict limits on Iranian enrichment will mean that even if Iran withdraws from the agreement to pursue a nuclear weapon, it would take at least six months to do so," the official said.