The report was promptly touted by Tehran as supporting Iran's stand that the U.S.-led calls for a third round U.N. Security Council sanctions on Iran over its refusal to halt uranium enrichment were unjustified.
The U.S. and its allies fear Tehran is using its civilian nuclear program as a cover to produce atomic weapons. Iran denies the charge, saying its program is solely geared toward generating electricity.
"The agency in this reported ended all the baseless U.S. accusations against Iran," Mohammad Saeedi, deputy head of Iran's Atomic Energy Organization, was quoted as saying by the state IRNA news agency.
"Once again the agency confirmed validity of Iran's stances," Saeedi said, adding that "the U.S. had deceived the world over Iran's nuclear activities by claiming that Iran was reprocessing plutonium."
"We do appreciate the agency for its professional approach toward the case and we are hopeful that it continues," Saeedi Was quoted as saying.
The report, released in Vienna, Austria, by the International Atomic Energy Agency, highlighted the importance of a recent deal with Tehran to have Iran answer the agency's key questions on past nuclear activities within an agreed timeframe.
If that and all other deadlines are adhered to and Iran provides all the information sought, the agency should be able to close the file on its more than four-year investigation of Tehran's past nuclear activities by year's end.
However, the report also said that Iran continued to expand the enrichment program and the building of a plutonium-producing reactor - although at a slower pace than expected.
Still, Saeedi said the report was "unprecedented" and that remaining issues between Iran and the agency over the Islamic Country's disputed nuclear activities can be settled through negotiations.