State media have reported that Iran will accept a UN deal on its nuclear programme only if "very important changes" are made.
Al Alam TV quoted "informed" sources as saying Tehran will respond to the International Atomic Energy Agency deal within 48 hours.
Under the draft proposal, Iran would send enriched uranium to Russia and France to be turned into fuel.
Iran missed a deadline last week for responding to the IAEA's proposal.
Al Alam said Iran would "accept the broad framework of the deal, but wants very important changes in it". No details were issued.
On Monday, Foreign Minister Manouchehr Mottaki said Iran was considering whether to send some uranium to other countries for enriching or to buy already enriched uranium.
The BBC reports all other parties have confirmed their support for the deal, which is seen as a way for Tehran to get the fuel it needs for an existing reactor, while giving guarantees to the West that enriched uranium will not be used for nuclear weapons.