ISTANBUL - Iran’s talks Saturday with six world powers aimed at easing tensions over Tehran’s nuclear programme were faring much better than the last failed attempt, with prospects good for another round, the European Union said.

“There is a positive atmosphere ... contrasting with the last time” in January 2011, Michael Mann, spokesman for EU foreign policy chief Catherine Ashton, told reporters at the meeting in Istanbul, saying they were “totally different.” “The principles for future talks seem to be there,” he said, adding that the venue and date for the next round of more detailed discussions - possibly in four to six weeks in Baghdad - would “probably be decided later today.” Other delegations in Istanbul were tight-lipped on progress. They were expected to hold a series of bilateral meetings before coming back for what they hope will be a final joint session later on Saturday.

Sources close to the Iranian delegation said that the US team has requested - via Ashton - what would be rare bilateral discussions with the head of the Iranian delegation, Saeed Jalili. No response has been made so far, the source said.

The last time Iran met with the United States, Russia, China, Britain, France and Germany - the so-called P5+1 - in January 2011 in Istanbul, it quickly became apparent that they would go nowhere.

The UN Security Council has imposed four rounds of sanctions on the Islamic republic because of suspicions that its civilian nuclear programme is a cover for a secret atomic weapons drive, a charge Iran vigorously denies. The international community’s main concern, particularly for Iran’s arch foe Israel, is Tehran’s growing capacity to enrich uranium, which can be used for peaceful uses but, when purified further, for a nuclear weapon.

Of particular worry is the formerly secret Fordo site in a mountain bunker near the holy city of Qom, currently enriching to 20-percent purity but which experts say could be reconfigured to produce 90-percent weapons grade material. Fordo’s expansion plus a major UN atomic agency report in November on alleged “weaponisation” efforts have led to tighter EU and US sanctions on Iran’s oil sector due to bite this summer, as well as talk of Israeli military strikes. Representing Washington in Istanbul was Wendy Sherman, undersecretary for political affairs. Ma Zhaoxu, assistant foreign minister, led the Chinese delegation, while Deputy Foreign Minister Sergei Ryabkov headed Moscow’s team. Ahead of Saturday’s talks Western powers stressed that they were in no mood for a repeat of previous doomed attempts at resolving once and for all the Iranian nuclear issue.

As he seeks re-election this November, US President Barack Obama in particular is wary of being accused by his Republican challenger of being duped by empty Iranian promises that just buy Tehran more time.

Obama, who has warned against “loose talk” of war, said last month that “both the Iranian and the Israeli governments recognise that when the United States says it is unacceptable for Iran to have a nuclear weapon, we mean what we say.”

“I don’t bluff,” he said.

At the same time all parties in the talks, not least energy-hungry China, want the crisis resolved in order to bring down oil prices to help the stuttering global economy.

Whether a second round of talks would succeed remains to be seen, however, with Iran likely to insist on the right to a peaceful nuclear programme while demanding sanctions be eased.

US media reports have suggested that the P5+1 want Iran to halt all enrichment of uranium to purities of 20 percent, shutter Fordo and send Tehran’s stockpiles of enriched uranium abroad, where they cannot be used for a bomb.

The world powers also want Iran to grant the International Atomic Energy Agency greater access to ease fears that it might have covert facilities, and to answer accusations made in the IAEA’s November report.