A leaked IAEA report found last month that, as of June, Iran had 440kg of enriched uranium stockpiled, while Grossi told NZZ that the agency believes it still has around 400kg.
And he emphasised that, following the bombardment, the IAEA would require the “full cooperation” of Tehran, which “will only happen if Iran sees it as a national interest”.
He went on: “Will we get access to this uranium? And what will happen to it then? Will Iran want to keep it, will it reduce its enrichment levels again, or will Iran move this uranium abroad?
"Sitting down together at the table saves us the danger of another round of bombing and attacks.”
Iran cut ties with the IAEA in the wake of the attacks, later re-establishing relations under a new framework, which will only allow UN inspectors into nuclear sites if they are approved by Tehran’s security services.
It comes after the UN reactivated punishing economic sanctions against Iran over its failure to fully cooperate with the agency.
The move, authorised under the “snapback” provision in the 2015 Joint Comprehensive Plan of Action (JCPOA), was activated by the E3 nations – France, Germany and the UK.
The EU also confirmed that it would follow suit, with measures imposed against Iranian interests on the continent.
These include asset freezes on a number of Iranian financial institutions, including the Iranian Central Bank, as well as travel bans on several officials and prohibitions on the sale or transport of Iranian oil within the bloc.