UN Security Council members, along with Germany, will meet in Vienna to progress a package of incentives and threats to be presented to Tehran.
Western nations – especially the US – fear that Iran is enriching uranium in a bid to create a nuclear weapon, not for civil energy use as the Iranian regime claims.
Britain, France and Germany have been pressing for measures designed to end the deadlock.
And on Wednesday Ms Rice announced the US would join direct talks with Iran if it halted nuclear activities.
But Russia and China – which both wield vetoes at the council – have made clear they would not accept any implicit threat of the use of force.
On Wednesday night Ms Beckett said the US would “give added weight” to the Vienna talks.
“We are all striving to reach a diplomatic solution,” she added.
“The European side’s goal is to present a serious and substantial offer of co-operation, which demonstrates to Iran the benefits that would flow from compliance with the IAEA’s successive resolutions, rather than the further isolation which would result from their failure to do so.
“I urge Iran to respond positively to this opportunity.”
