U.N. atomic watchdog chief Rafael Grossi told his agency's Board of Governors on Wednesday that negotiations he had held in Tehran this week over Iran's nuclear programme had proved inconclusive.
Grossi returned from Tehran on Tuesday after meeting the head of Iran's Atomic Energy Organization and Iran's foreign minister as he sought to strike a deal with Iran to reinstall four of his agency's cameras at a centrifuge-parts workshop that was the victim of apparent sabotage.
But he appeared to return without progress leaving a thorn in the side of relations between Iran and the West days before indirect talks between Tehran and Washington over reviving the battered 2015 Iran nuclear deal resume on Monday.
"Despite my best efforts, these extensive negotiations and deliberations to address Iran's outstanding safeguards issues, detailed in the two reports, proved inconclusive," Grossi told the 35-nation Board of Governors at the start of its quarterly meeting, according to the text of the speech sent to reporters.
He was referring to reports recently issued by the agency.
The standoff over the Karaj workshop that makes parts for advanced centrifuges, machines that enrich uranium, is one of several issues that have soured relations between Iran and the IAEA and angered Western powers that say Tehran must back down.
The IAEA also wants answers from Iran on the origin of uranium particles found at several apparently old but undeclared sites, and has told its member states that Iran keeps subjecting its inspectors to "excessively invasive searches, which resulted in them feeling intimidated" during security checks.
The United States and its European allies would normally pressure Iran on those issues by trying to pass a resolution against it at the quarterly meetings.
With the wider talks on the 2015 deal due to resume on Monday after a five-month break, however, diplomats say it is unlikely there will be any such attempt for fear of jeopardizing those talks.