Foreign Minister Manouchehr Mottaki said EU foreign policy chief Javier Solana was expected in Tehran in the coming days to officially submit the proposal for fresh multilateral talks and a package of incentives.

But the five permanent members of the Security Council plus Germany, who agreed on the package on Thursday, say the offer is conditional to Tehran first halting enrichment -- at the centre of fears the country could make nuclear weapons.

"Negotiations must be without preconditions," Mottaki said of the demand. "No condition for negotiations is acceptable, especially the condition that has been set."

But he nevertheless said Iran "needed to examine these proposals" before giving its formal response.

"Javier Solana will be in Tehran in the next two days to submit the new proposals to Iran," Mottaki was quoted as saying by the official Irna news agency, adding that Iran had agreed to his visit.

European diplomats confirmed that Solana was set to travel to Tehran, but said the timing had yet to be fixed.

US Secretary of State Condoleezza Rice said Friday that Iran had only weeks to respond to the proposal of trade, security and technology incentives if Iran agrees to a moratorium on enrichment.

Crucially, the United States has also promised to join the talks if Iran agrees -- paving the way for what could be the most substantive talks between the two arch-enemies since they cut off diplomatic ties 26 years ago.