Iran has denied receiving a proposal from Moscow to build a joint uranium enrichment facility in Russia.
An Iranian Foreign Ministry spokesman, Hamid Reza Asefi, told a news conference Sunday that Tehran has received no such proposal, and would only consider proposals that recognize Iran's right to enrich uranium on its own soil.
Russia said Saturday its embassy in Tehran presented Iranian authorities with a note saying its offer to set up a joint uranium enrichment facility in Russia remains valid.
Under a deal signed earlier this year, Moscow agreed to supply enriched uranium fuel for Iran's Bushehr reactor. But Russia also demanded the return of spent fuel to ensure Tehran did not reprocess it into bomb-grade material.
The United States and the European Union say Tehran is using its nuclear program to develop atomic weapons. Iran says it is only for peaceful purposes.
Some information for this report provided by AP, AFP and Reuters.