"The Iranian interest in the Kalinin station is obvious -- a similar energy bloc, with the VVER-1000 reactor, is being built in Iran with the help of Russian experts," the Rosenergoatom said in a statement, adding that this would not be the first Iranian visit to the site.

The United States and the European Union fear that Iran is developing nuclear weapons under cover of its civilian nuclear energy program, which has been developed with Russia's assistance.

Tehran has rejected that assertion and said it has no plans to stop uranium enrichment work which it says is strictly for energy generation.

The five permanent UN Security Council members -- Britain, China, France, Russia and the United States -- together with Germany presented an incentives package to Iran on June 6.

These incentives include support for Iran's nuclear energy program and economic cooperation, but are conditioned on Tehran's suspension of uranium enrichment and full cooperation with the UN's nuclear watchdog agency.

Earlier Monday Russia said its position on Iran's nuclear program was unchanged on the eve of Tehran's anticipated response to an offer from world powers aimed at persuading Iran to halt uranium enrichment.