Grossi said inspectors have returned to some facilities but were restricted to sites that were not damaged in the attacks.

The IAEA chief said three other sites – Natanz, Isfahan, and Fordow – are even more significant, since they still contain substantial amounts of nuclear material and equipment. He said restoring full access is the key issue and the agency is maintaining dialogue with Iran, but so far the level of cooperation has been limited.

The IAEA says verification of Iran's stockpile of enriched uranium, particularly material close to weapons-grade level, is "long overdue" and this issue needs to be addressed urgently.

Following the airstrikes, Iran reduced its cooperation with the IAEA and announced that all future IAEA requests for inspections must be approved by the Supreme National Security Council of Iran.