By Parisa Hafezi and Fernando Exman
TEHRAN (Reuters) - Iran made an apparent concession over its nuclear programme, but big powers expressed scepticism and analysts said the move seemed intended to split the international community and avert planned new U.N. sanctions.
Tehran agreed with Brazil and Turkey on Monday to send some of its uranium abroad, reviving a fuel swap plan drafted by the U.N. with the aim of keeping its nuclear work in check.
But Iran made clear it had no intention of suspending domestic enrichment the West suspects is aimed at making bombs.
"There is no relation between the swap deal and our enrichment activities," Ali Akbar Salehi, head of Iran's Atomic Energy Organisation, told Reuters.
He told Iranian television the deal was a move towards nuclear cooperation and "stopping sanctions."
Iran launched work to enrich uranium to a 20 percent level in February. Further enrichment would be needed to make weapons.
The White House said Iran must take steps to prove its nuclear programme was for exclusively peaceful purposes.
"Given Iran's repeated failure to live up to its own commitments ... the United States and international community continue to have serious concerns," a spokesman said.
"I think we are making steady progress on a sanctions resolution."
A State Department spokesman said the United States would "engage Iran anywhere, anytime, provided Iran is prepared to address the international community's concerns about its nuclear program," but would continue to pursue new sanctions.
Turkish Foreign Minister Ahmet Davutoglu called the fuel swap deal a "historic turning point."
"My expectation is that after this declaration there will not be a need for sanctions," Turkish Prime Minister Tayyip Erdogan said, echoing a statement by Brazil.
Britain said work on a new U.N. sanctions resolution must go on. Iran's move "may just be a delaying tactic," said Foreign Secretary William Hague.
France said the deal would not resolve core concerns.
"Let us not deceive ourselves, a solution to the (fuel) question, if it happens, would do nothing to settle the problem posed by the Iranian nuclear programme," French Foreign Ministry spokesman Bernard Valero said in a statement.
Russian President Dmitry Medvedev expressed similar concern. "One question is: will Iran itself enrich uranium? As far as I understand from officials of that state, such work will be continued. In this case ... those concerns that the international community had before could remain," Medvedev said.
But he said he would discuss the issue later in the day with Brazilian President Luiz Inacio Lula da Silva.
"After this, we need to decide what to do: Are those proposals sufficient or is something else needed? So I think a small pause on this problem would not do any harm," he said.
Washington has been leading a push to impose new sanctions, and especially to win the backing of permanent U.N. Security Council members Russia and China.
Analysts say Monday's agreement may allow Tehran to stave off a fourth round of sanctions and help the leadership reassert its authority after months of anti-government unrest that followed a disputed presidential election last June.
A European Commission spokesman said the deal might be a step in the right direction, but details needed to be seen.
AHMADINEJAD CALLS FOR MORE TALKS
Lula, Erdogan and Iranian President Mahmoud Ahmadinejad clinched the agreement after hours of talks in Tehran, Iranian state media reported. Turkey and Brazil are both non-permanent members of the U.N. Security Council.
Iran said it had agreed to transfer 1,200 kg (2,646 lb) of its low-enriched uranium (LEU) to Turkey within a month and in return receive, within a year, 120 kg of 20 percent-enriched uranium for use in a medical research reactor.
Iran, which says its atomic programme is purely for peaceful purposes, had earlier insisted any such transfers must take place simultaneously and on its territory.
"Iran expressed its readiness to deposit its LEU within one month. On the basis of the same agreement the Vienna Group should deliver 120 kg fuel required for Tehran research reactor in no later than one year," a joint declaration said.
Iranian Foreign Ministry spokesman Ramin Mehmanparast said Iran's LEU would be under the supervision of the Vienna-based International Atomic Energy Agency in Turkey. The IAEA would be notified within a week about the swap deal, he said.
Ahmadinejad called on the five permanent Security Council members -- the United States, Russia, China, France and Britain -- and Germany to open new negotiations with his country.
"They should welcome the major event that took place in Tehran and distance themselves from the atmosphere of pressure and sanctions to create an opportunity for interaction and cooperation with Iran," he said.
Western diplomats say Iran is trying to give the impression that the fuel deal is at the centre of problems with the West, rather than its nuclear ambitions as a whole.
They also said removing from Iran 1,200 kg of LEU -- enough, if highly enriched, to make a nuclear weapon -- was less significant now than when it was first proposed because in the months of wrangling over the original IAEA swap deal, Iran's low-enriched uranium stockpile has almost doubled.
(Additional reporting by Ramin Mostafavi in Tehran, Fredrik Dahl in Dubai, Simon Cameron-Moore in Ankara, Sylvia Westall in Vienna; Chris Buckley in Beijing; Luke Baker in Brussels; Erik Kirschbaum and Madeline Chambers in Berlin; Adrian Croft in London; Moscow bureau; writing by Andrew Roche; editing by Myra MacDonald)