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…

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.