VIENNA: More than two months after US President Barack Obama's re-election opened the way for new six-power nuclear talks with Iran, no date or location for their first meeting since June has been set.

The apparent scheduling woes have combined with recent comments from an Iranian official to raise concerns that the unprecedented sanctions pressure imposed on Iran over its nuclear programme has failed to make the country more pliable -- on the contrary even.

Insiders had hoped that once Obama was free from the constraints of his lengthy re-election campaign, conditions would be favourable to make progress in the long-running crisis over Iran's nuclear intentions.

At first there were hopes that Iran would sit down with the P5+1 -- Britain, China, France, Russia, the United States, and Germany -- in December to talk about its controversial nuclear programme, which Western nations suspect is aimed at developing the bomb.

This then slipped to January, of which one week remains.

The latest proposal out of Tehran on Wednesday from Foreign Minister Ali Akbar Salehi was for Cairo, but he gave no date. A top Russian official said Istanbul before the end of February was a possibility.

A spokesman for EU foreign policy chief Catherine Ashton, the chief negotiator for the P5+1, told AFP that "concrete dates and venue" were proposed in December and that the six countries -- the five permanent members of the UN Security Council plus Germany -- were "very flexible".

But the spokesman, Michael Mann, indicated that the date and the city were not the problem.

Iran has "come back to us again and again with new pre-conditions on the modalities of the talks, for example by changing the venue and delaying their responses", he said.

A new "analysis" by Mahdi Mohammadi, a member of Iran's negotiating team, posted at http://www.iranreview.org on January 9, indicates that Iran and the P5+1 remain poles apart.

He said that the United States and the European Union "should remove all unilateral sanctions against Iran and Iran, for its part, will take immediate steps to address the remaining concerns of the International Atomic Energy Agency (IAEA)."

Only then, he said, will Iran be "ready to negotiate about 20-percent enrichment provided that the United Nations Security Council will annul all its sanctions resolutions against Tehran".

For the P5+1 this is the wrong way around.

Iran's growing capacity to enrich uranium to fissile purities of 20 percent is for the six powers the most worrisome part of its nuclear programme, because if further enriched it could be used in a bomb. Iran denies this is its aim.

In Baghdad in May, the P5+1 called on Iran to suspend 20-percent enrichment, close its Fordo nuclear facility and ship abroad the uranium it has already processed. Mohammadi made no mention of either of these last two demands.

The six made no concrete pledge in May to ease sanctions in return, leading Iran to walk away from the following round of talks in Moscow in June.

Tehran has been slapped by multiple sets of UN sanctions for its refusal to stop enrichment. The US and the EU have also imposed additional sanctions.

"If the multilateral sanctions are lifted too soon in the negotiating process, should the negotiation ultimately fail it may be very difficult to restore them," Mark Hibbs from the Carnegie Endowment for International Peace told AFP.

Deeper cooperation between Iran and the IAEA, meanwhile, in particular letting the UN body investigate suspected past nuclear weapons research, is important but has not been a make-or-break issue for the P5+1.

Mohammadi's mention of it suggests that Iran might use the issue as a bargaining chip, analysts say. Iran's failure last week to reach a deal with the IAEA could also be seen as another sign of Tehran talking tough.

Mark Fitzpatrick from the International Institute for Strategic Studies said that Iran may be engaging in "pre-negotiation negotiation, trying to smoke out the six powers on what might be offered on sanctions relief."

"I wouldn't be surprised if this stage of pre-talk negotiations drags on for a while," Fitzpatrick told AFP. "But it is dangerous for Iran to play with this game."

Cliff Kupchan from political risk consultancy Eurasia said that sooner or later the two sides will have to meet.

"As January ticks away I think structural reality will set in for both sides. The Obama administration would very much like to resolve this issue diplomatically," Kupchan told AFP.

"The Iranians have severe economic difficulties right now... and sanctions are just going to get worse. Iran is certainly not dealing from a position of strength."