Grossi told Russia’s RIA Novosti that inspectors had returned to some facilities but were restricted to sites that were not damaged in the attacks.
“We are only allowed to access sites that were not hit,” he said, calling the resumption important but insufficient.
“These other three sites – Natanz, Isfahan and Fordow – are even more significant, since they still contain substantial amounts of nuclear material and equipment, and we need to return there.”
He said determining whether there had been “any practical progress” in restoring full inspections remained the agency’s most pressing issue in Iran.
Israel launched strikes on Iranian nuclear and military targets on June 13, accusing Tehran of pursuing a covert nuclear weapons program – a charge Iran denies.
The attacks were followed by 12 days of hostilities, with the United States joining with a one-off strike on Iranian nuclear facilities on June 22. Iran responded with missile strikes on a US air base in Qatar, saying it did not seek further escalation.
Iran’s foreign ministry has said a recent IAEA resolution would complicate dialogue over Tehran’s nuclear program.
The agency has long sought access to Natanz, Isfahan and Fordow, where enrichment and other sensitive activities have taken place, and says oversight at those locations is critical to verifying Iran’s nuclear commitments.