The International Atomic Energy Agency (IAEA) said in a report seen by AFP last Friday that Iran has for months blocked inspections at two sites where nuclear activity may have occurred in the past.

The Vienna-based agency noted "with serious concern that, for over four months, Iran has denied access to the agency... to two locations".

In a note to the IAEA dated June 8, Iran said it had held meetings with agency representatives in Tehran on April 29 and May 16 to discuss the access issues, followed by written correspondence and a fresh proposal to meet with IAEA representatives.

In the note circulated by Tehran's mission to the UN in Vienna on Thursday, Iran insisted it "continued its constructive engagement with the agency during the past two months, with a view to reach a common understanding... which would pave the way for the resolution of concerned issues."

Iran argues that the requests for access are based on "fabricated information", accusing the United States and Israel of trying to "exert pressure on the agency".

Israel has claimed that its intelligence services have new information on Iran's alleged previous nuclear weapons programme.

The IAEA has said previously that its access requests were based on "concrete information" that had been validated.

In its note, Iran expressed "deep regret and disappointment" at the IAEA's latest report.

The report is expected to be discussed at a meeting of the agency's board of governors starting next Monday.

In a separate report, also to be discussed during the board meeting, the IAEA warned that Iran's enriched uranium stockpile is now almost eight times the limit set in the nuclear deal the country signed with world powers in 2015.

Iran has been progressively breaking restrictions laid down in the 2015 deal in retaliation for US withdrawal from the accord in 2018 and its subsequent re-imposition of sanctions.