The United States told Iran today it must change its nuclear course or be isolated, but Tehran remained defiant despite the spectre of harsher sanctions as it held talks on its atomic work with the European Union.
US Secretary of State Condoleezza Rice said it was time for Iran to abandon uranium enrichment work. But EU foreign policy chief Javier Solana acknowledged before he met Iran's top nuclear negotiator in Madrid it would be hard to clinch a deal.
"It is time for Iran to change its tactics. The international community is united on what Iran should do and this is to suspend (enrichment of uranium for nuclear fuel)," Ms Rice said during a visit to Vienna.
Mr Solana's meeting with Iran's Ali Larijani at a former hunting estate outside Madrid looked like a last stab at easing the tense standoff over Iran's expanding efforts to produce nuclear fuel before world powers sharpen UN sanctions.
But no one held out hope for a breakthrough compromise one month after the last inconclusive session between the two men, despite the threat of tougher, broader sanctions on Iran.
"It is true that as time goes by, if the situation continues, probably the agreement will be more complicated," Mr Solana said before the talks. "I will try to ... see if we can pave the way in order to get into formal negotiations."
Major powers insist Iran stop enriching uranium as a confidence-building precondition for negotiations on trade and other benefits offered to Tehran a year ago.
Mr Larijani yesterday ruled out a nuclear halt as demanded by the UN Security Council, offering only to assure its programme is not a disguised bid for bombs as the West suspects. Iran says it only wants atomic power to generate electricity.
Foreign ministers of the Group of Eight top industrialised nations, meeting in Germany on Wednesday, expressed "deep regret" Iran had not only failed to stop enriching by a UN deadline of May 24th but widened the programme.
They said "further appropriate measures", code language for sanctions, were on the cards if Iran did not back down quickly.
Enrichment is a process of refining uranium for power plants or, if taken to a very high degree, atomic bombs.
A report by the watchdog International Atomic Energy Agency (IAEA) last week laid bare how Iran was accelerating a campaign to install 3,000 enrichment centrifuges by mid-summer, laying a basis for "industrial-scale" fuel production.