Such a purified uranium ore deal would be significant because Tehran appears to be running out of the material, which it needs to feed its uranium enrichment program.
The report was drawn up by a member nation of the International Atomic Energy agency and provided to the AP on condition of that the country not be identified because of the confidential nature of the information.
Such imports are banned by the U.N. Security Council.
In New York, Burkina Faso's U.N. Ambassador Michel Kafando, a co-chair of the Security Council's Iran sanctions committee, referred questions Tuesday about a potential deal between Iran and Kazakhstan to his sanctions adviser, Zongo Saidou.
Saidou told the AP that, as far as he knew, none of the U.N.'s member nations have alerted the committee about any such allegations. "We don't have any official information yet regarding this kind of exchange between the two countries," Saidou said. "I don't have any information; I don't have any proof."
A senior U.N. official said the agency was aware of the intelligence report's assessment but could not yet draw conclusions. He demanded anonymity for discussing confidential information. A Western diplomat from a member of the IAEA's 35-nation board said the report was causing "concern" among countries that have seen it and generating "intelligence chatter." The diplomat also requested anonymity for discussing intelligence information.
A two-page summary of the report obtained by the AP said deal could be completed within weeks. It said Tehran was willing to pay $450 million, or close to 315 million euros, for the shipment.
The price is high because of the secret nature of the deal and due to Iran's commitment to keep secret the elements supplying the material," said the summary. An official of the country that drew up the report said "elements" referred to state employees acting on their own without approval of the Kazakh government.
After-hours calls put in to offices of Kazatomprom, the Kazak state uranium company, in Kazakhstan and Moscow, were not answered Tuesday. Iranian nuclear officials also did not pick up their telephones.
Purified ore, or uranium oxide, is processed into a uranium gas, which is then spun and re-spun to varying degrees of enrichment. Low enriched uranium is used for nuclear fuel, and upper-end high enriched uranium for nuclear weapons.
Iran is under three sets of U.N. Security Council sanctions for refusing to freeze its enrichment program and related activities that could be used to make nuclear weapons.
Tehran denies such aspirations, saying it wants to enrich only to fuel an envisaged network of power reactors.