Iran says it is not opposed to sending its low-enriched uranium abroad for further enrichment, as long as it receives fuel for its nuclear reactor at the very same time.
Foreign Ministry Spokesman Ramin Mehmanparast told reporters Tuesday that Tehran wants a 100 percent guarantee that there will be a simultaneous exchange on Iranian soil.
Iran has so far resisted a proposed U.N.-backed deal intended to ease Western concerns about Tehran's nuclear program.
Under that plan, Iran would send more than 70 percent of its low-enriched uranium stockpile to Russia and France. The uranium would be converted into fuel rods and returned to Iran in about a year for use in an Iranian medical research reactor.
Western nations say Iran's nuclear program is aimed at creating weapons, but Tehran insists it is for peaceful purposes.
The five permanent members of the U.N. Security Council, plus Germany, are considering tougher measures against Iran for stalling on the deal. But China and Russia are reluctant to put on more pressure.
Tehran is already under international sanctions for its failure to halt uranium enrichment activities.