The International Atomic Energy Agency has had no information from Iran on the status or whereabouts of its stock of highly enriched uranium, IAEA chief Rafael Grossi said.
Grossi sent two reports on Iran to member states making clear there had been no breakthrough.
Both reports said an agreement paving the way for inspections to resume "should be concluded without delay" and that Iran's stock of highly enriched uranium is "a matter of serious concern".
In late June, Iran has passed a law suspending cooperation with the IAEA and stipulating any future inspections will need a green light from Iran's Supreme National Security Council. Tehran and the IAEA are now in talks on how inspections can go ahead.
Technically, inspections in Iran have resumed since IAEA inspectors recently carried out a mission at Bushehr, Iran's only operating nuclear power plant, but it is of so little concern from a proliferation perspective that it does not generally feature in quarterly IAEA reports on Iran.