By ELAINE SCIOLINO
PARIS - Iran on Sunday backed off a demand to operate uranium enrichment equipment that could be used either for energy purposes or in a nuclear bomb-making project, European and Iranian officials said.
The Iranian retreat appeared to salvage a nuclear agreement reached Nov. 15 between Iran and France, Britain and Germany to freeze all of Iran's uranium enrichment, conversion and reprocessing activities.
It also paves the way for the 35 countries that make up the ruling board of the International Atomic Energy Agency, the Vienna-based United Nations nuclear monitoring body, to pass a resolution that will be only mildly critical of Iran's nuclear program.
Such a resolution, expected to be passed Monday, is certain to disappoint the Bush administration, which is convinced that despite Iran's denials, it has a covert program to build nuclear bombs, not simply to produce energy. The administration had wanted much tougher language in the resolution.
Iran's suspected nuclear ambition has become a leading source of worry in the Bush administration, which has said it will not allow Iran's Islamic republic, with its avowed hostility to the United States, to attain nuclear weapons or even develop a comprehensive peaceful nuclear energy program. In Washington, reports of a new accord with Iran brought expressions of caution from the Bush administration, which has been skeptical about the European efforts to negotiate with Iran.
"We've seen this kind of commitment from Iran before," a State Department official said. "We'll be looking to see whether they stick with what they agree to do. In the past they haven't, so follow-up is very important."
The retreat came in the form of a letter from Iran on Sunday to the International Atomic Energy Agency. In the letter, Iran withdrew its demand to operate 20 centrifuges - uranium enrichment machines - for research and development purposes.
"Iran will permit the I.A.E.A. to place these centrifuges under agency surveillance," said Hossein Mousavian, the chief Iranian negotiator, in a telephone interview from Vienna. "Iran will not conduct any testing."
Asked specifically whether the machines would be turned off, as the Europeans have demanded, Mr. Mousavian said, "We say Iran will not conduct any testing," adding that the matter of Iran's desire to continue research will be discussed when Iran and the European countries begin talks in the coming weeks on possible economic, technological and political incentives for Iran under the European agreement.
After the letter was received, the three European countries formally submitted a draft resolution on Iran to the United Nations agency, said Mark Gwozdecky, the agency's spokesman.
The I.A.E.A. is expected to certify Monday that Iran has frozen its entire program as defined by the agreement with the Europeans.
That will allow the agency's board to pass the resolution on Iran on Monday as well. Unlike the United Nations Security Council, where 5 of the 15 member countries have veto power, the I.A.E.A.'s board generally operates by consensus.
The Bush administration has been continually frustrated in its efforts to persuade the atomic energy agency to punish Iran for its nuclear activities. The three European countries have rejected a flurry of American proposals for a harshly worded resolution against Iran.
The breakthrough between the Europeans and Iran came after Iran suggested a change in the resolution that would more specifically reflect the positive step Iran was taking in suspending its enrichment program, both Mr. Mousavian and a senior European official said. In exchange, Iran abandoned its demand to operate the centrifuges for research.
Mr. Mousavian said the 20 centrifuge machines would not be sealed but placed under camera surveillance, a face-saving move that the I.A.E.A. said would be acceptable in terms of its monitoring capacity.
In another face-saving gesture, the Iranians said in their letter to the agency on Sunday that there would be no "testing," rather than no "research and development."
But a senior European official involved in the negotiations said that under the new arrangement, "The machines will not rotate an inch."
Despite its softer language, the resolution to be adopted Monday calls for continuing investigations into sensitive aspects of Iran's nuclear program.
The resolution also mentions "many breaches of Iran's obligations to comply" with international nuclear safeguards but notes Iran has taken "corrective measures" since beginning to disclose parts of its atomic program in October 2003.
Mr. Mousavian said Iran won a crucial change to reflect the fact that the freeze of its enrichment program was "not legally binding."
As a signer of the Nuclear Nonproliferation Treaty, Iran has the legal right to enrich uranium, and the Iranian delegation made the point repeatedly during the negotiations that its country's suspension of its uranium enrichment program was voluntary.
In Tehran on Sunday, Hamid Reza Assefi, a Foreign Ministry spokesman, said Iran hoped the issue would be resolved at the atomic energy agency. Nonetheless, he struck a defiant tone.
"We are not worried about going to the Security Council," he said. "It is not the end of the world. But we would prefer it be sorted out in the framework of the agency."
There is no national security debate inside Iran that is more intense than over the country's nuclear program, from the highest levels of government to Parliament and the street.
Iranians of all political stripes hold fast to the principle of Iran's sovereign right to conduct whatever activities it deems necessary to develop a peaceful program to produce energy, and the agreement with the Europeans has been wildly unpopular inside Iran.
Iran had agreed in negotiations with the Europeans two weeks ago to suspend all uranium enrichment activities. But that agreement was put in jeopardy last week when Iran demanded that it be allowed to operate centrifuges for research purposes. That demand came in two letters to the International Atomic Energy Agency from Iran's atomic energy agency, whose hard-liners oppose any concessions to outsiders.
But Iran misread the Europeans. At first, the Iranian delegation tried to argue that the centrifuge issue was only a technical matter. Iranian negotiators pointed out that after Iran had reached its first nuclear deal with the Europeans in October 2003, it continued to operate 10 centrifuges for research purposes and both the Europeans and the agency went along.
"With that history and everyone's agreement, we couldn't imagine that a few centrifuges would become a worldwide issue this time," Mr. Mousavian said.
But that first deal with the Europeans fell apart. Iran decided that the Europeans were stalling on delivering promised incentives and interpreted the agreement broadly to continue some uranium enrichment-related activities.
The Europeans were accused of naïveté by some hawks in the Bush administration, and have become less trusting of Iran. This time around, the Europeans negotiated a more precise deal and took an uncompromising no-exceptions line when the centrifuge issue was raised.