Iran called the intelligence report, which was cited by the Associated Press, part of a psychological war.
"Such fabrications of news are part of the psychological warfare [against Iran] to serve the political interests of the hegemonic powers," Iran's representative at the United Nations was quoted by Reuters as saying.
Kazakhstan earlier also denied any plans to supply uranium to Iran.
The IAEA believes Iran is running out of uranium reserves which may hamper its controversial nuclear program, which the Islamic nation claims it needs purely for civilian energy production. A report drafted by an IAEA member nation said Tehran could make some 150 nuclear warheads from 1,350 tons of uranium ore.
U.S. Department of State Spokesman Ian Kelly warned that "the transfer of any uranium yellowcake... to Iran would constitute a clear violation of UNSC sanctions."
Iran, which is already under three sets of United Nations sanctions for refusing to halt uranium enrichment, recently announced plans to build 10 new uranium enrichment facilities. Western powers suspect it of pursuing an atomic weapons program.