"The Europeans have continuously demanded a halt to enrichment but this demand was not included in the agreement... The Europeans must accept Iran's uranium enrichment," said Sirus Nasseri, referring to an initial deal reached with the EU last year.

Britain, France and Germany have been trying to secure "objective guarantees" that Iran will not use its atomic energy ambitions to acquire nuclear weapons, and in exchange they are offering a package of trade, security, diplomatic and technology benefits to the Islamic republic.

"The negotiations have progressed well in the political and economic committees, but in the nuclear committee there has been less progress," said Nasseri, who led the Iranian team in talks last week in Geneva with EU negotiators Britain, France and Germany.

He stressed that the negotiating period was not "indefinite" and if no "reasonable agreement" were reached, Iran would be prepared to break off the talks and "accept the consequences".

Tehran agreed in November to suspend its enrichment activities as a sign of goodwill, but the Europeans would like the suspension to become a permanent halt, a demand the Iranians have termed "absurd".

Iran says it has the right to enrich uranium to produce atomic fuel for civilian power stations, but once mastered the fuel cycle can be diverted to military purposes.

Nasseri also urged the United States "to be reasonable and to change its strategy on Iran", warning that such a move would be "in the Americans' best interest."

Washington accuses Iran of using an atomic energy drive as a cover for weapons development, and has threatened to take the matter to the UN Security Council.

Iran and the Europeans held a fourth round of negotiations last week that ended in a deadlock. A top level meeting between the two sides to evaluate the progress in the talks is to be held on March 23.

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