The foreign ministers of Turkey, Iran and Brazil meet in Istanbul Sunday for talks on a nuclear fuel swap deal they brokered to resolve the standoff over the Islamic republic's atomic drive.

The meeting will be the first such gathering since Iran was slapped in June with new UN sanctions over its controversial nuclear programme, some two weeks after it struck a deal with Brazil and Turkey to send some of its uranium stockpiles abroad in return for nuclear fuel.

Turkish Foreign Minister Ahmet Davutoglu first met his Brazilian counterpart Celso Amorim over breakfast at a luxury Istanbul hotel for talks on the Middle East. The two men are expected to hold a joint press conference at 0800 GMT.

They will then be joined by Iran's Manouchehr Mottaki at a luncheon for consultations on the prospects of a peaceful resolution to the row over Tehran's nuclear programme. It was not clear whether there would a statement afterwards.

The three-way talks were arranged after Mottaki "expressed his desire to meet both (Davutoglu and Amorim), taking advantage of the Brazilian foreign minister's trip to Turkey" as part of a Middle East tour, a foreign ministry statement said.

Turkey will pursue efforts to facilitate a diplomatic solution to the nuclear problem and the resumption of long-frozen talks between world powers and Iran, it added.

Iran, Brazil and Turkey reached the fuel swap deal, know as the Tehran Declaration, on May 17.

Under the declaration, Iran agreed to send 1,200 kilogrammes of its low-enriched uranium (LEU) to Turkey to be supplied at a later date with high-enriched uranium by Russia and France.

But it was immediately cold-shouldered by world powers which went ahead and backed a fourth round of sanctions against Iran on June 9 over its refusal to halt its sensitive uranium enrichment programme.

The deal was a counter-proposal by Iran to an October plan drafted by the UN nuclear watchdog, the International Atomic Energy Agency (IAEA), in collaboration with Russia, France and the United States -- the trio since known as the Vienna group -- in a bid to keep Tehran's uranium stockpiles in check.

That plan became deadlocked, with each group insisting on conditions unacceptable to the other.

The group raised several questions regarding the Tehran Declaration, and Iran's atomic chief Ali Akbar Salehi said on Saturday that Tehran had prepared its response and would deliver it "in the next two or three days".

Salehi was quoted by the ISNA news agency as saying that Iran's response was a "general response, but the technical response to their questions will be discussed probably in a meeting with the Vienna group."

He did not specify when such a meeting might take place.

Iran is expected to commence talks with the six world powers -- Britain, China, France, Russia, the United States and Germany -- concerning its overall nuclear programme from September.

Hardline President Mahmoud Ahmadinejad, under whose leadership Iran has aggressively pursued its nuclear programme, ordered a freeze on these talks until the end of August.

The latest UN sanctions were followed by unilateral punitive measures from Washington, and on Thursday the European Union agreed on a package of punitive measures targeting Iran's energy sector.

Western powers have demanded that Iran suspend uranium enrichment, fearing Tehran would use the material to make a nuclear bomb. Tehran says its atomic programme is peaceful.

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