"Enrichment should be carried out on Iranian soil, as other Iranian officials have said before," foreign ministry spokesman Hamid Reza Asfi told reporters.

That position was spelled out on Saturday by Iran's Atomic Energy Organisation head Gholamreza Aghazadeh after a meeting with Igor Ivanov, the head of Russia's Security Council.

According to diplomats, Russia and the West are looking at a proposal whereby Iran would outsource sensitive enrichment abroad and maintain less sensitive facilities at home.

Iran says it only wants to enrich uranium to low levels for atomic reactor fuel, although the process can be diverted to military purposes.

It was still not clear exactly what offer Ivanov had presented to the Iranians and the Russian official insisted that he had come with no specific proposal.

"As far as I know there is no such proposal (on enrichment)," Asefi said, describing Ivanov's visit as "positive".