The Washington Post said an advanced program could shorten Iran's path to building atomic weapons.
The purchase orders show Iranian agents attempting to buy 100,000 of the magnets from China about a year ago, but it is unclear whether Iran purchased and obtained the magnets, the Post said.
The White House refused to comment directly on the report, instead urging Tehran to return to talks on its nuclear program. Deputy press secretary Josh Earnest said the United States is "well aware of Iran's aggressive efforts in violation of its U.N. Security Council Resolution obligation to obtain sensitive materials for its uranium-enrichment program" but that sanctions "have choked the supply of critical components for Iran's nuclear program."
Under U.N. resolutions, the magnets are banned from export to Iran, the Post reported.
Analysts said although Iran has often attempted to buy banned items, the size of the order is very unusual -- and concerning.
The news of the orders coincides with the country's recent announcement it will build thousands of centrifuges for the production of more enriched uranium, the Post said.
Although Iran insists its nuclear program is peaceful, the attempt is concerning many who fear a nuclear Iran.
"They are positioning themselves to make a lot of nuclear progress quickly," said a European diplomat who spoke to the Post on a condition of anonymity said. "Each step forward makes the situation potentially more dangerous."