By Hashem Kalantari
TEHRAN (Reuters) - Iran voiced optimism about Turkish and Brazilian mediation efforts in its nuclear dispute with the West, welcoming in principle ideas aimed at reviving a stalled fuel deal with major powers.
"New formulas have been raised about the exchange of fuel ... I think we can arrive at practical agreements on these formulas," Foreign Ministry spokesman Ramin Mehmanparast said in remarks published by the daily Iran newspaper on Saturday.
"That is why we welcomed the proposals in principle ... and left the details for more examination."
He did not elaborate on the content of the proposals -- which have revolved around Iran sending low-enriched uranium abroad for further processing into fuel -- or say when they were presented.
His comments appeared to be part of an Iranian attempt to avert a new round of U.N. sanctions on Tehran over a nuclear program the West fears is designed to develop bombs. Iran, a major oil producer, says it only seeks to generate electricity.
Analysts say Iran may be trying to buy time and to split the six world powers -- the United States, Britain, France, Germany, Russia and China -- which are discussing imposing more punitive steps against the Islamic Republic.
Turkey and Brazil, currently non-permanent members of the United Nations Security Council, have been trying to resuscitate the fuel proposal in a bid to stave off further sanctions on Iran that are sought by the United States and its allies.
Brazilian President Luiz Inacio Lula da Silva will travel to Tehran at the end of next week to work on a negotiated solution with Iran, his foreign minister told Reuters on Friday.
Iran's semi-official Mehr News Agency said Turkish Prime Minister Tayyip Erdogan would also be in Tehran on May 16, but his office said there were currently no such plans.
President Mahmoud Ahmadinejad earlier this week agreed "in principle" to Brazilian mediation on the proposed fuel swap exchange, Iranian media reported.
The plan is seen as a way to remove much of Iran's low-enriched uranium (LEU) stockpile to minimize the risk of this being used for atomic bombs, while Iran would get specially processed fuel to keep its nuclear medicine program running.
But the proposal broke down over Iran's insistence on doing the swap only on its territory, rather than shipping its LEU abroad in advance, and in smaller, phased amounts, meaning no meaningful cut in a stockpile which grows day by day.
Western officials have dismissed an Iranian counterproposal.
The United States is lobbying U.N. Security Council members to back sanctions including proposed measures targeting Iranian banks, shipping and the country's all-important energy sector.
But Brazilian Foreign Minister Celso Amorim told Reuters his country saw a window of opportunity and a willingness by Iran to reach a negotiated solution over its nuclear program. He met Ahmadinejad in Tehran last week.
Russia and China, permanent members of the Security Council which have significant commercial links with Iran, have said they are willing to give Turkey and Brazil more time.
Brazil favours a mooted compromise in which Iran could export its uranium to another country in return for higher-enriched fuel for a Tehran research reactor. Iran has so far insisted the exchange must take place on its territory.
"The framework set out by the countries (Turkey and Brazil), alongside our own country's recent proposal, has the potential from the perspective of Iran for arriving at a final common point and becoming operational," Mehmanparast said.
"At any rate, we believe the efforts being undertaken by friendly countries, such as Turkey and Brazil, can ultimately be positive," he added.
(Additional reporting by Thomas Grove in Istanbul; writing by Fredrik Dahl; editing by Myra MacDonald)