World Focus: Can the West believe Ahmadinejad when he starts to talk peace?

Iran seems to be making conciliatory noises in the stand-off with the West over its nuclear ambitions. On Tuesday, Tehran's top nuclear negotiator signalled that it had new proposals for Western governments.

Last night diplomats said that they believed Tehran could request a resumption of talks on its disputed nuclear programme before world leaders gathering at the United Nations later this month debate tough new sanctions.

After a meeting of the five permanent members of the UN Security Council plus Germany in Koenigstein, a German foreign ministry official signalled such a hope.

Divining the motives of Iran remains hazardous, however, with analysts warning that the regime of President Mahmoud Ahmadinejad, which remains deeply distracted by internal turmoil sparked by his re-election, may be trying only to muddy the waters ahead of the critical meetings in New York.

US President Barack Obama, supported by Britain, Germany and France, has continued his dual-track approach, offering engagement provided that Iran responds to demands that it cease its uranium enrichment activities, while insisting that it do so this month or face new sanctions. These could include a block on imports into Iran of refined oil products including petrol.

The stakes for all sides are higher than ever. Re-engagement with so-called rogue regimes is a main plank of Mr Obama's foreign policy vision. But he can wait only so long for Iran to take the carrot, not least because of pressure from Israel and its murmurings of military strikes.

Making the dossier more complicated is the underlying linkage with Mr Obama's hope that he can announce a breakthrough on Middle East peace.

American diplomats are aware that Israeli Prime Minister Benjamin Netanyahu may hold any such breakthrough hostage to a resolution of the Iranian issue.

All the players, including Mr Netanyahu and Mr Ahmadinejad, will be at the United Nations General Assembly in New York that opens on 23 September.

Iran may be seeking to offer just enough between now and then to relieve some of the pressure – or to weaken the resolve of the permanent five. Russia and China remain unenthusiastic about approving more punitive action.

Two weeks ago, Iran reached a new agreement with the International Atomic Energy Agency (IAEA) in Vienna to allow inspectors to return to its yet-to-be-completed heavy water plant near Arak and also to improve conditions for camera monitoring at the main nuclear facility of Natanz.

Iran continues to insist that its nuclear industry is geared towards civil purposes only. Much will now depend on what exactly is contained in its reported new plan.

Javier Solana, the EU foreign policy chief, said: "I haven't received it and I cannot judge it. If the document is presented, we will read it and we will be happy to discuss it."

London and Washington are pointing to the latest critical report from the IAEA on Iran's conduct as evidence that the time has come to get tough on the regime.

"It has become much clearer that there is a case on the possible military dimension of their nuclear programme that has to be answered," one diplomat said yesterday. "And they are still to do that."

It is not clear to anyone how far Iran can move, in part because of the continuing internal turbulence. Yesterday, it emerged that 40 of its ambassadors abroad are to be sacked. The clear-out seems aimed at those who showed sympathy for "rioters" who protested after the June elections.

The move is surely evidence that the crackdown by regime hardliners (those who are the least likely to give ground in any nuclear talks) is not yet over. It remains to be seen whether this signifies their grip on power, or their weakness.