Vienna International Centre, where IAEA offices are located
Vienna International Centre, where IAEA offices are locatediStock

Iran on Wednesday said it has supplied the United Nations’ nuclear watchdog with documents explaining the discovery of suspect enriched uranium traces, The Associated Press reported, citing Iranian state media.

The head of Iran's civilian Atomic Energy Organization, Mohammad Eslami, said Iran sent the requested explanations on March 20 about several former undeclared sites in Iran where there was evidence of past nuclear activity.

The deadline came as part of an agreement announced last month to resolve the problem of undeclared uranium particles in Iran by June, long a source of tension between Tehran and the UN’s International Atomic Energy Agency (IAEA).

Last year, the IAEA found uranium particles at two Iranian sites it inspected after months of stonewalling.

Although the sites where the material was found are believed to have been inactive for nearly two decades, opponents of the 2015 nuclear deal Iran signed with world powers say evidence of undeclared nuclear activities shows that Iran has not been acting in good faith.

Eslami told reporters on Wednesday that Iran had handed over documents to the UN watchdog about the three requested sites in Iran, without elaborating. He expected agency inspectors to visit Iran “to review the answers" and finish a report on the subject by late June, he added.

The Vienna-based IAEA declined to comment on Eslami’s remarks.

The report comes as nuclear talks between Iran and world powers on a return to the 2015 deal continue.

Iran has gradually scaled back its compliance with the 2015 deal, in response to former US President Donald Trump’s withdrawal from the agreement in May of 2018, but has held several rounds of indirect talks with the US on a return to the agreement.

Negotiations nearly reached completion last month before Moscow demanded that its trade with Iran be exempted from Western sanctions over Ukraine, throwing the process into disarray.

On Wednesday, US Secretary of State Antony Blinken said he was "not optimistic" about the prospects to revive the 2015 Iran nuclear deal.