Ali Larijani, the chief negotiator, has also reiterated Iran's threat to renew enrichment activities if it is referred to the UN Security Council.
After talks with Russian Security Council chief Igor Ivanov, which included discussion of the plan to enrich uranium in Russia, Larijani said: "Our view of this offer is positive, and we are trying to bring the positions of the sides closer."
"This plan can be perfected in the future, during further talks that will be held in February," he said, speaking through a translator.
Larijani suggested that it would take some time to work out details of Russia's proposal.
Some critics say the Iranians are using the proposal to stall for time as diplomatic pressure on Tehran mounts over its alleged nuclear weapons programme.
"There are lots of details surrounding this offer that must be examined," Larijani said.
On Tuesday, Larijani and Ivanov said in a joint statement Tehran's nuclear stand-off must be resolved through the UN atomic watchdog agency's diplomatic efforts.
The statement reflected Russia's efforts to delay Iran's referral to the Security Council and Moscow's opposition to international sanctions against Tehran.
The IAEA's 35-nation board will
meet on 2 February
After the two met, Russia's Security Council said: "Both sides expressed their desire to solve the issue in a diplomatic way within the framework of the International Atomic Energy Agency."
Iran has said that IAEA referral to the Security Council over its nuclear ambitions will lead it to move forward with a full-scale uranium enrichment programme, a possible precursor to making atomic weapons.
High-level diplomacy has intensified with little more than a week to go until the 2 February meeting of the IAEA's 35-nation board.
Prior to that session, Condoleezza Rice, the US secretary of state, will attend an international conference in London on 31 January focusing on Afghanistan.
However, Sean McCormack, a department spokesman, said Rice was expected to use the meeting to have discussions with key nations on Iran's nuclear programme.
The New York Times reported that the foreign ministers of the five permanent members of the UN Security Council - Britain, France, Russia and China, in addition to the US and Germany - would attend the meeting.
Iran maintains it only wants
civilian nuclear energy
Moscow has proposed having Iran's uranium enriched in Russia, then returned to Iran for use in the country's reactors - a compromise that could provide more oversight and ease tensions.
Haggling has continued over the specifics of the proposal, including Tehran's proposal to have China involved in the Russian enrichment process.
Jack Straw, the British foreign secretary, urged Tehran on Tuesday to seriously consider Russia's offer to enrich Iran's uranium, in an effort to end the stand-off.
Straw also said in an interview with The Associated Press he hoped the IAEA would refer the matter to the Security Council.
The West fears that Iran wants to develop a nuclear bomb, but Tehran says its intentions are peaceful and that it wants only civilian nuclear energy.