"Iran provided Agency inspectors access to the location to take environmental samples," according to an International Atomic Energy Agency (IAEA) report on Friday.
"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.
On June 19, the Board of Governors passed a resolution, put forward by Britain, France and Germany – the three European signatories to the landmark 2015 nuclear agreement, officially known as the Joint Comprehensive Plan of Action (JCPOA), to push for inspections of two sites that the trio claims may have been used for undeclared nuclear activities in the early 2000s.
It was the Israeli regime’s spy service that first came up with the allegations of such activity at the two sites. Iran has, however, strictly rejected the allegations.