PITTSBURGH: Russia's President Dmitry Medvedev urged Iran on Friday to cooperate fully with the UN nuclear watchdog in any probe of its newly revealed second enrichment plant.

Medvedev did not, however, raise the threat of sanctions, which Western powers have demanded if Tehran refuses to engage in dialogue on ending its uranium enrichment program.

Instead, the Russian leader said Iran should show "convincing proof of its intention to develop nuclear energy solely for peaceful aims" at talks with the international community on October 1.

"Exposed evidence that Iran is building a new enrichment plant only strengthens our determination to achieve concrete and verifiable results in the nearest future," Medvedev said.

"We call on Iran to fully cooperate with the International Atomic Energy Agency," Medvedev said in a statement read out by his spokeswoman Natalya Timakova at the Group of 20 economic summit in Pittsburgh.

"Russia maintains a commitment to serious dialogue with Iran with a view to reaching agreement on efficient ways to remove the concerns of the international community over this country's nuclear program."

The statement appears to fall short of expectations by the West that Russia, which has close ties with Iran, would support calls for sanctions.

Just on Wednesday the Russians had delighted Washington when Medvedev, attending the UN General Assembly in New York, indicated a policy shift on Iran by saying that in some cases sanctions were "inevitable".

A top Russian official said Moscow would cooperate if there was "sufficient" proof that Iran continued to enrich uranium, which Western powers fear could be used to make a nuclear bomb.

Russia's apparent move on the issue had followed Obama's decision to scrap a missile shield plan for Europe, which had angered Moscow. Russian diplomats acknowledged in private that Moscow had felt obliged to return the favor.

A top Russian diplomat, speaking to AFP on the sidelines of the G20 summit, refused however to say whether Russia considered Iran's second plant "sufficient" proof of its intention to develop nuclear arms.

Instead, Medvedev pledged full cooperation with the UN's nuclear watchdog.

"The Russian side together with other partners believes the IAEA should immediately study the situation in the context of the existing inspection activities with regards to Iran's nuclear program," Medvedev said.

"As part of the obligations Russia has taken upon itself as an International Atomic Energy Agency member, we will facilitate such an inspection in any way possible for us," he added.

It was Britain, France and the United States that used the summit backdrop earlier Friday to make the dramatic announcement that Iran had admitted to the IAEA that it had secretly built it second nuclear enrichment plant.

Russia will join these powers plus China and Germany on October 1 for talks with Iran. France and Britain have warned that if these talks do not produce progress on the nuclear issue then they would call for tough sanctions.