Iran agreed to the deal with the International Atomic Energy Agency (IAEA) in Cairo, after it suspended cooperation following its war with Israel in June.

The 12-day war saw Israeli and US strikes on key Iranian nuclear facilities, which IAEA inspectors have not been able to access since.

Addressing the opening day of the agency's annual General Conference, IAEA chief Rafael Grossi said it was now to implement the deal "to restore confidence" and allow the agency "to continue our work in spite of all these difficulties".

"Now it's up to... Iran and us to implement" the deal that "summarises the technical measures, the practical steps that we need... to resume this indispensable work in Iran," Grossi said in his speech.

Tehran has said the new framework grants access to UN nuclear inspectors only after approval by its Supreme National Security Council, Iran's top security body.

In his statement to the general conference, Iran's atomic energy organisation chief Mohamed Eslami said that following the attacks on its nuclear sites, "continued cooperation with the agency will be pursued through new arrangements once the security concerns of our nation and our nuclear facilities are addressed".

"Currently, no provision has been provided for the safeguards agreement as to how to continue engagement on the very critical situations following the aggression and continuation of threats against nuclear sites and facilities," he said.

But he added that Iran "remains a state party" to the Non-Proliferation Treaty (NPT) treaty despite passing a law that halted cooperation with the IAEA.

Western powers have repeatedly expressed concern about the expansion of Iran's nuclear programme, which Tehran stepped up after the United States unilaterally withdrew from a landmark 2015 deal on limiting its nuclear programme.

Iran has long been accused of seeking to acquire nuclear weapons, a claim it denies.