France and Russia have urged Iran to halt its uranium enrichment programme after Tehran confirmed on Tuesday it had resumed the work.
Western powers suspect Iran's nuclear ambitions are not peaceful
The French prime minister and Russian president issued a joint statement calling on Iran to conform in full with the demands of the UN's nuclear agency.
Iran on Tuesday confirmed it resumed small-scale uranium enrichment work at the Natanz plant last week.
Western nations suspect Iran is trying to build nuclear weapons.
Uranium enrichment is one part of that process. However, Tehran insists its nuclear programme is solely for peaceful purposes.
The joint statement was posted on the Kremlin's official website, following French Prime Minister Dominique de Villepin's visit to Moscow.
"Russia and France call on Iran to fully comply with the February resolution and the demands of the board of governors of the International Atomic Energy Agency," said the statement.
The IAEA resolution reported Tehran's nuclear programme to the UN Security Council.
The move could lead to eventual sanctions against Iran, although any action has been put off until a report by the head of the IAEA on 6 March.
Iran responded by ending snap UN checks of its facilities and vowing to resume uranium enrichment.
France and Russia said they recognised Iran's right to pursue a peaceful nuclear programme for energy.
They also said the international community supported Russia's proposal to enrich uranium on its territory for Iranian nuclear power plants.
At a joint news conference with Mr de Villepin, Russian Prime Minister Mikhail Fradkov said he was concerned about how "events were unfolding" around Iran's nuclear programme.
However, he said the potential for a positive outcome was "not yet exhausted".
Senior Iranian nuclear negotiator Javad Vaidi said Tehran would send a delegation to Russia for talks on 20 February to discuss the proposal to enrich uranium on Russian soil.
Iran had postponed the talks after being reported to the Security Council.
Despite the IAEA resolution, Mr Vaidi said Iran was still prepared to discuss Russia's proposed compromise.
"We are still ready for negotiations with everyone including the Europeans, the Non-Aligned Movement, China, Russia and others. We want to achieve a formula through interaction and understanding," he said.
"We call on the West not to create any problems for us, because we do not intend to cause any for them."
Mr Vaidi said it would be "unacceptable" for Iran to halt research on the enrichment process, whatever the IAEA decided at its March meeting.