"The agenda, time and venue of the talks is not set yet, but both sides will first hold the talks on the experts level then on the higher level," the spokesman for Iran's supreme national security council, Hossein Entezami was quoted as saying.

He was responding to an offer by the EU-3 to resume direct talks with the Islamic republic on its nuclear programme. Washington accuses Iran of using it as a cover for nuclear weapons development, charges vehemently rejected by Tehran.

"It does not make any difference whether the talks are official or unofficial, the important thing is to talk. However the talks should have a time frame," he added.

On Sunday, a diplomat told AFP that the foreign ministers of EU-3 have written to Iran's top national security official Ali Larijani with an offer of new direct talks on Iran.

According to the semi-official Mehr news agency on Sunday, the letter was handed to Javad Vaidi -- one of Iran's negotiating team -- in response to a letter from Larijani which called for a resumption of negotiations.

Entezami reaffirmed Tehran's insistance that it would enrich uranium on Iranian soil, saying it had not received any proposals from Russia on moving its enrichment facilities abroad.

Iranian Foreign Minister, Manouchehr Mottaki said at a press conference during a visit to Azerbaijan on Monday that Tehran has a right to enrich uranium as part of its nuclear energy program, saying "no force" can stop it from doing so.

"The enrichment of uranium is Iran's internal affair. It is the right of any state and no force can prevent the state from exercising this right." he said.