The UN's nuclear watchdog said Friday that Iran had granted its inspectors access to one of two sites where undeclared nuclear activity may have taken place in the early 2000s.
"Iran provided Agency inspectors access to the location to take environmental samples," an International Atomic Energy Agency (IAEA) report said.
"The samples will be analysed by laboratories that are part of the Agency's network," it added.
An inspection at the second site will take place "later in September 2020 on a date already agreed with Iran," the report said.
Iran announced last week it would allow the IAEA access to the two sites, following a visit to Tehran by IAEA Director General Rafael Grossi.
Iran had denied the agency access earlier this year, prompting the IAEA's board of governors to pass a resolution in June urging Iran to comply with its requests.
In a separate report also issued on Friday, the IAEA said Iran's stockpile of enriched uranium now stands at more than ten times the limit set down in the 2015 nuclear deal with world powers.
The limit was set at 300 kilogrammes (661 pounds) of enriched uranium in a particular compound form, which is the equivalent of 202.8 kg of uranium.
Measured against the latter figure, Iran's stockpile now stands at over 2,105 kg, the report said.
