In a televised interview, Araghchi said "all of our material is... under the rubble of the bombed facilities", adding that the Atomic Energy Organization of Iran was assessing the condition and accessibility of the material in order to submit a report to the country's Supreme National Security Council.

Araghchi said the council -- Iran's top security body -- was in charge of the country's nuclear affairs.

His remarks came after he agreed on Tuesday in Cairo a deal with UN nuclear watchdog chief Rafael Grossi on a new framework of cooperations with the International Atomic Energy Agency.

In his interview on Thursday, Araghchi insisted that the new cooperation framework agreement grants access to UN nuclear inspectors only after the approval of Iran's security body.

Iran halted its cooperation with the agency following the 12-day war with Israel in June, following a law passed by the Iranian parliament.

Iran has accused the IAEA of failing to adequately condemn Israel's strikes.

In his joint press conference from Egypt on Wednesday, Araghchi said the framework was "fully consistent" with provisions of the law.

Araghchi on Thursday further elaborated that the agreement distinguishes between nuclear facilities that were attacked during the war and others which were unharmed, such as the Bushehr reactor in the south.

Access to undamaged facilities will be "considered case by case by the Supreme National Security Council", he said, adding that the situation for the targeted facilities was more "complicated".

"For now no action is taken until Iran carries out the necessary measures related to environmental and safety concerns," he noted, referring to the hit sites.

During an interview with CBS in late June, Grossi had admitted that "we don't know where this (highly enriched) material could be".

US President Donald Trump had nonetheless insisted that Iran's nuclear programme had been set back "decades".

Iran had an estimated 408.6-kilo (900-pound) stockpile of highly enriched uranium before the attacks.

Iran insists its nuclear programme is for peaceful purposes, while Western countries accuse Tehran of seeking an atomic weapon -- a charge Tehran has denied.

In August, Britain, France and Germany initiated steps to reimpose UN sanctions after weeks of warnings, citing Iran's continued non-compliance with its commitments under a largely moribund 2015 nuclear agreement.

Araghchi said that "if the issue of activating the snapback mechanism goes through in the Security Council despite all the disputes, from our point of view this agreement will no longer be valid".