Iran reiterated today it would not bow to US and European demands that it abandon uranium enrichment.
Tehran stood defiant on the nuclear issue as US President George W. Bush started a European tour which will include discussions on Iran and other foreign policy issues.
Mr Sirus Naseri, a senior member of Iran's negotiating team
Washington and the European Union both want Tehran to scrap uranium enrichment, a process which can be used to make fuel for nuclear power plants or bomb-grade material.
But the United States has refused to join an initiative by the EU - represented by France, Germany and Britain - to offer Iran incentives to curtail its nuclear programme.
"I believe the European countries have eventually understood that Iran's nuclear capability is not for sale," said Mr Sirus Naseri, a senior member of Iran's negotiating team engaged in talks about the nuclear issue with the EU.
"The final agreement in these negotiations will be based on the continuation of (uranium) enrichment by Iran," Mr Naseri said.
"We will give the Europeans an opportunity to reach this stance but this opportunity won't be permanent," he added.
Iran says it has no intention of building nuclear weapons and has said it is prepared to provide "objective guarantees" that its nuclear facilities will not be used to make bombs. But it has not said what those guarantees could be.