Iran has slowed its enrichment of uranium but has not clarified the "possible military dimensions" of its disputed nuclear program with international nuclear investigators, the UN's atomic watchdog agency said in a report Friday.

The reactor building of Iran's Bushehr nuclear power plant is seen in April 2007. (Bagher Nasir/Mehr News Agency/Associated Press)In its latest report circulated to member nations, the International Atomic Energy Agency said it has pressed Tehran to clarify its uranium enrichment activities and reassure the world that it's not trying to build an atomic weapon, according to reports from several media organizations that had obtained a copy of the document.

In the report, the IAEA acknowledged that Tehran has been producing nuclear fuel at a slower rate and has allowed UN inspectors broader access to its main nuclear complex in the southern city of Natanz.

The latest report from the watchdog comes ahead of six-power talks on Iran set for Sept. 2, and a key meeting of the IAEA's 35-nation board in two weeks.

Following the report's release, the U.S. State Department said it shows Iran is continuing to defy the international community.

Iran's chief representative to the IAEA, Ali Asghar Soltanieh, dismissed the report as "very frustrating" and angrily suggested that U.S. intelligence was working to undermine Tehran's credibility.

"All these things are fabrications. We have been too transparent and co-operative with the agency," he was quoted as saying.

The United States and European nations have threatened to push for increased sanctions against Tehran if the Islamic regime continues its nuclear activities.

Oil-rich Iran has denied allegations from the West and Israel that it is trying to produce an atomic weapon and insists its enrichment program is for the peaceful purpose of providing a stable supply of electricity.

The UN Security Council has scheduled a meeting in September to discuss whether to bring further sanctions against Tehran.

With files from The Associated Press