Iran today spurned a US offer of direct talks on its nuclear programme as major world powers sought agreement on incentives to coax it to scrap potentially weapons-related atomic work.
Foreign Minister Manouchehr Mottaki said Iran was open to talks with Washington, which severed ties with Tehran in 1980, but rejected a US condition it stop enriching uranium first.
"We will not give up our nation's natural right [to enrichment], we will not hold talks over it. But we are ready to hold talks over mutual concerns," Mr Mottaki said in Tehran.
Speaking before Mr Mottaki's statement, a senior US official said Tehran had only weeks to accept the diplomatic overture before facing sanctions.
Crude oil prices fell below $71 a barrel today, deepening losses sparked by the US offer of talks.
Defying UN Security Council calls for it to halt nuclear fuel work, Tehran announced in April that it had produced its first batch of enriched uranium.
Foreign ministers of the five permanent UN Security Council powers plus Germany and the EU foreign policy chief were arriving in Vienna to finish the incentives package for Iran.
Washington's overture was a big policy shift that a senior US official said had won over Russia and China to pursuing UN sanctions against Tehran if it spurned the sweeteners.