 "Iran, world powers seek comprehensive nuclear deal")
Expectations were not high, however, ahead of the scheduled three-day Vienna meeting between Iran and the United States, China, Russia, Britain, France and Germany, the first in a likely series of tricky encounters.
Iran's supreme leader Ayatollah Ali Khamenei said yesterday he was "not optimistic" and that he expected the talks to "lead nowhere" -- although he also said he was not against the negotiations.
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Iranian Foreign Minister Mohammad Javad Zarif was more upbeat after a dinner yesterday with the chief negotiator for the six powers, EU foreign policy chief Catherine Ashton.
"We believe we can reach an agreement and we have come here with the political will to reach a final agreement," Zarif was quoted by Iran's ISNA news agency as saying, adding however that it "will take time".
"It is probably as likely that we won't get an agreement as it is that we will," said one senior US administration official for the talks. "But these negotiations are the best chance we have ever had."
Iran has long been suspected of seeking atomic weapons, despite its denials, and the US and Israel -- widely assumed to have a formidable nuclear arsenal itself -- have never ruled out military action.
Foreign ministers from the seven countries struck a deal in Geneva on November 24 that was widely hailed as an enormous breakthrough after a decade of failed diplomatic efforts and rising tensions.
Under the accord, which took effect on January 20, Iran scaled back certain nuclear activities in exchange for minor relief from painful sanctions and a promise of no new ones.
For the first time the West accepted Iran enriching uranium, a process producing nuclear fuel but potentially also material for a bomb, having earlier wanted a total suspension.
But the freeze only lasts until July 20 - although it can be extended - and experts say that success in Geneva came at the price of postponing discussions on really tough issues.
"Geneva really was a stop gap, a band-aid solution that didn't really heal the wounds," Siavush Randjbar-Daemi, Iran and Middle East lecturer at Manchester University, told AFP.
Under the "comprehensive" solution that the parties want by November, the six powers want Iran to cut back permanently - or at least for a very long time - its nuclear programme.
This might include closing the underground Fordo facility, slashing the number of centrifuges enriching uranium, cutting the stockpile of fissile material and altering a new reactor being built at Arak.
This, plus much tighter UN inspections, would not remove entirely Iran's capability to get the bomb but would make it substantially more difficult.
In exchange, all UN Security Council, US and EU sanctions on Iran - which are costing it billions of dollars every week in lost oil revenues, shredding the economy - would be lifted.