World leaders will launch an eleventh hour push to defuse a potential deadly Middle East conflict over the threat from a nuclear Iran, prioritising diplomatic efforts after the US elections.
Iran, currently mired in economic crisis, is expected to be offered temporary relief from existing sanctions, in exchange for limiting its uranium enrichment.
A European official told the Guardian six powers, US, UK, France, Germany, Russia and China, will meet with the Iranian chief negotiator, Saeed Jalili, in late November or December, but the direction of the talks is likely to hinge on whether Mitt Romney or Barack Obama is president of the US.
The official told the Guardian: "We recognise that the Iranians need something more with which they can sell a deal at home, and we will expect real change on the other side. It is about getting the sequencing right. That is what this next round will be about."
Britain's Mark Sedwill, formerly the UK's special envoy to Afghanistan and Pakistan, and the new political director of the Foreign Office will lead the British talks.
Officials are worried a Romney win could "derail diplomatic efforts" with Jalili uninterested in talks until the outcome of the US election is known, and the result of the forthcoming Israeli elections.
Foreign Policy magazine's David Rothkopf said that sources in the Obama administration had questioned if he really supported military action on Iran.
"Despite the president's regular assurance that Iran will not be allowed to develop nuclear weapons and that force will be used if necessary, the American people's war fatigue in the wake of Iraq and Afghanistan has made any complex, costly, or highly risky action a tough political sell back home."
Ordinary Iranians are currently reeling from soaring prices, with the official inflation rate 23%, but much higher in practice. President Mahmoud Ahmadinejad has been the target of angry street protests.
The crisis has been blamed on a US and EU ban of sales of Iranian oil and business deals with the Bank of Iran.
The rial has lost 75% of its value against the dollar.
UN Secretary General Ban Ki-moon said in a report: "The sanctions imposed on the Islamic Republic of Iran have had significant effects on the general population.
He pinpointed "an escalation in inflation, a rise in commodities and energy costs, an increase in the rate of unemployment and a shortage of necessary items, including medicine."
European foreign ministers are due to meet in Luxembourg on Monday to agree more sanctions, potential bans on more Iranian banks and tightening shipping restrictions.
Holding a childlike drawing of a bomb, with a lit fuse, Israel's prime minister Benjamin Netanyahu told the UN General Assembly last month: "At this late hour, there is only one way to peacefully prevent Iran from getting atomic bombs and that's by placing a clear red line on Iran's nuclear weapons program.
"Red lines don't lead to war; red lines prevent war. Iran uses diplomatic negotiations to buy time to advance its programme.
"The international community has tried sanctions, has passed some of strongest sanctions. Oil exports have been curbed, and the Iranian economy has been hit hard. But we must face the truth that sanctions have not stopped Iran's nuclear drive."
He stressed that the US and Israel were in "discussions" on the issue.
Netanyahu is currently well ahead in the polls as Israelis prepare for a forthcoming election.