The International Atomic Energy Agency faces a range of difficulties in Iran, including the fact it only implemented a small fraction of the steps IAEA chief Rafael Grossi thought it committed to in a "Joint Statement" on cooperation last year.

A previous warning said Tehran has enough uranium enriched to near-weapons-grade levels to make "several" nuclear bombs if it chose to do so, and the country continues increasing stockpile.

The efforts are under the guidance of Iran’s supreme leader and unlikely to change after last week’s helicopter crash that killed Iran’s president and foreign minister.