By DAVID E. SANGER
But the overtures, made through the International Atomic Energy Agency over the past two weeks, have all been ignored, the officials said. Instead, they said, the Iranians have revived an old counterproposal: that international arms inspectors take custody of much of Iran’s fuel, but keep it on Kish, a Persian Gulf resort island that is part of Iran.
A senior Obama administration official said that proposal had been rejected because leaving the nuclear material on Iranian territory would allow for the possibility that the Iranians could evict the international inspectors at any moment. That happened in North Korea in 2003, and within months the country had converted its fuel into the material for several nuclear weapons.
The intermediary in the exchanges between Washington and Tehran has been Mohamed ElBaradei, the director general of the energy agency. He confirmed some of the proposals — including one to send Iran’s fuel to Turkey, which has nurtured close relations with Iran — in interviews in New York late last week.
But members of the Obama administration, in interviews over the weekend, said that they had now all but lost hope that Iran would follow through with an agreement reached in Geneva on Oct. 1 to send its fuel out of the country temporarily — buying some time for negotiations over its nuclear program.
“If you listen to what the Iranians have said publicly and privately over the past week,” one senior administration official said Sunday, “it’s evident that they simply cannot bring themselves to do the deal.” The administration officials spoke on the condition of anonymity because they were speaking about delicate diplomatic exchanges.
Iranian officials told the energy agency on Oct. 29 that they could not agree to the deal that their own negotiators had reached, but they never explained why. Iran has never publicly rejected the deal, but its official reaction has been ambiguous at best.
Dr. ElBaradei insisted he still had hope, but he conceded that the chances were receding.
“I have been saying to the Iranian leadership, privately and publicly, ‘Make use of that opportunity. Reciprocate,’ ” Dr. ElBaradei said last week. But he said that it now appeared that “the foreign policy apparatus in Iran has frozen,” partly because of the country’s own domestic turmoil.
So far, President Obama has said nothing about the stalemate threatening his first, and potentially most important, effort at diplomatic engagement with a hostile foreign government. When the first meeting in Geneva ended Oct. 1, Iranian and American officials said they would meet again later in the month to discuss the nuclear program and the potential for a broader relationship. That meeting never occurred, and none is scheduled.
Mr. Obama’s aides say he is still willing to wait until year’s end before concluding that Iran is rejecting his offers of diplomatic engagement. What happens after that is unclear: Mr. Obama has suggested he would then turn to much more severe sanctions than the United Nations has already imposed against Iran, though it is unclear whether Russia and China would go along.
Officials in Israel, which feels the most threatened by Iran, have hinted that if Iran does not accept the Geneva deal they will revive their consideration of a military strike against Iran’s nuclear facilities. Mr. Obama’s own aides say they cannot determine whether the Israelis are bluffing.
Iran’s backpedaling from the Geneva deal — which would require Iran to ship 2,600 pounds of low-enriched uranium to Russia by Jan. 15 for processing into fuel rods for a reactor in Tehran used for medical purposes — will almost certainly be discussed when Mr. Obama meets the Israeli prime minister, Benjamin Netanyahu, at the White House on Monday evening.
In public, Mr. Netanyahu expressed support for the deal after it was announced. Privately, Israeli officials here said they expected it to fall apart because they doubted the Iranian government would part, even temporarily, with the fuel it had spent years accumulating.
Administration officials say they had been working closely with Russia each step of the way, and were pleased over the weekend that the Russian president, Dmitri A. Medvedev, had raised anew the prospect of economic sanctions if Iran rebuffed the offer. Russia has an economic interest in the deal: it would reap considerable revenue for converting Iran’s fuel — a step that Turkey would not be able to perform — and Russian officials appear to still be pressing the Iranians to take the deal.
“Russian efforts may well prompt Iran to accept,” an administration official said Sunday. “There is still time for Iran to make the right choice” before the board of the I.A.E.A. meets later this month.
But few other American or European officials interviewed in recent days seem to believe that the Iranians will agree to send the fuel to Russia, Turkey or any other nation. Officials would not say which other nations would possibly accept the fuel.
Officials say they believe that President Mahmoud Ahmadinejad of Iran, who first suggested the country might be willing to export its uranium temporarily, may have never expected that suggestion to be considered seriously. Some officials speculate Mr. Ahmadinejad’s offer may have been overruled by other Iranian authorities.
The idea of offering to help Iran use its stockpile to fuel the medical reactor attracted Mr. Obama because it would buy him time. Iran has generated enough fuel to make between one and two weapons — if it were further enriched — and it would take Iran roughly a year to replace the fuel it sent out of the country. That would take the pressure off some of the negotiations.
For that reason, it touched off a nationalistic backlash in Iran, and Mr. Ahmadinejad was criticized by both reformers and hard-liners. “The countries which were proposed to receive our 5 percent uranium were not countries that the Islamic republic trusts to trade with,” Hosein Naghavi-Hosseini, a member of Iran’s Majlis Security Council, said over the weekend, according to Iran’s state-run press, “because in the past, these countries have not held up their side of trade agreements.”
Iran’s supreme leader, Ayatollah Ali Khamenei, used the 30th anniversary of the takeover of the American Embassy in Tehran last week to warn Iranians against Mr. Obama’s offers of diplomatic engagement.
Mr. Obama is reported to have sent Ayatollah Khamenei two private letters this year, but he received only one response, mostly a litany of past grievances.
Robert F. Worth contributed reporting from Beirut, Lebanon.
