Iran's president, Mahmoud Ahmadinejad, is in Istanbul today for a regional economic summit which also gives him the opportunity to discuss with his Turkish hosts renewed efforts to resolve Tehran's nuclear dispute with world powers.
Turkey - Nato's sole Muslim member which has long-standing ties with the United States and a flourishing new relationship with Iran - has assumed a key mediating role in the tense stand-off.
Turkey's Islamist-rooted government insists on a diplomatic solution to the nuclear row and has resisted American entreaties to support a tougher line against the Islamic Republic.
Istanbul is scheduled to host in January Iran's next round of discussions with the five permanent members of the UN Security Council and Germany - the so-called P5+1 - after a frosty initial meeting in Geneva.
Today's summit of the Economic Co-operation Organisation (ECO), which groups Iran and Turkey with Pakistan and Central Asian states, is also the first international outing for Iran's caretaker new foreign minister, Ali Akbar Salehi.
He was appointed last week after Mr Ahmadinejad unceremoniously sacked Manouchehr Mottaki, who was close to the president's influential conservative rivals.
On assuming his post last weekend, Mr Salehi proclaimed that strengthening ties with Ankara was a priority for Tehran.
"Turkey is a powerful country, which is strategically positioned and shares common ideological and cultural ground with Iran," said Mr Salehi, who has retained his position as Iran's nuclear chief.
Western diplomats will closely monitor any public statements in Istanbul by Mr Ahmadinejad and Mr Salehi for signals of Iranian intentions in the forthcoming nuclear talks. The Iranian president, who usually enjoys the spotlight to trumpet a stridently anti-Western stance, struck an uncharacteristically conciliatory note last weekend, saying he hoped for a "win-win" outcome.
Mr Salehi is understood to be in favour of resolving the nuclear dispute although, like Mr Ahmadinejad, he insists on Iran's unconditional right to pursue peaceful nuclear technology.
Some analysts suspect Tehran may be prepared to curb parts of its nuclear programme in exchange for an end to punitive sanctions that, US officials insist, are hurting Iran far harder than it cares to admit.
The key to any deal is that Iran is allowed to continue enriching uranium, but under enhanced international supervision.
Britain's Daily Telegraph reported last week that, behind closed doors, Turkey was trying to broker an improved version of a confidence-building nuclear swap deal with Iran that it hammered out with Brazil in May. Under that accord, Iran would surrender a substantial part of its uranium stockpile in exchange for fuel plates to power an ailing medical reactor in Tehran. Washington rejected that accord, declaring that it would not sufficiently set back Iran's ability to develop a nuclear weapon.
With typical grandiloquence, Mr Ahmadinejad proclaimed yesterday that "arrogant powers" oppose Iran's nuclear programme not because they fear Tehran is striving for an atom bomb but because they are alarmed by Tehran's scientific prowess, which "will change tyrannical equations in favour of humanity".
In June, Turkey refused to back fresh sanctions against Iran, adopted at the UN Security Council, insisting its nuclear exchange initiative should be given a chance. Ankara's "no" vote peeved Washington, raising concern that Turkey was moving away from the West.
The US on Tuesday imposed new sanctions against Iran - primarily aimed at its Revolutionary Guards - to demonstrate that it will not ease the pressure despite renewed dialogue on Tehran's nuclear programme.
