Several experts have cautioned that Iran likely moved a stockpile of near weapons-grade highly enriched uranium out of the deeply buried Fordow site before the strikes and could be hiding it.

A preliminary assessment from the US Defense Intelligence Agency last week indicated that the strikes may have delayed Iran's nuclear programme by only a few months. But the Trump administration dismissed the assessment as low-confidence, claiming that newer intelligence showed Iran’s nuclear programme had suffered significant damage.

The new assessment contrasted with U.N. agency view that Iran could resume enriching uranium in a “matter of months.”