By STEVEN R. WEISMAN
WASHINGTON, Sept. 8 - The Bush administration's campaign to persuade Iran to abandon its suspected nuclear weapons programs is running into resistance among some allies and disputes over the seriousness of a new Iranian offer to suspend part of its activities, administration officials said Wednesday.
The officials said Iran made the offer during negotiations with the three European nations - Britain, France and Germany - that are trying to get Iran to abandon its nuclear ambitions and avoid punitive action sought by the United States.
The informal Iranian offer has not been made public, but officials who say they have seen details describe it as involving a suspension of some of Iran's nuclear programs in return for normal relations with the West and an end to threats of sanctions.
The United States has demanded that Tehran give up all its uranium enrichment activities, saying they are needed only to produce weapons, not electricity. On Wednesday, Secretary of State Colin L. Powell said he had seen reports of the Iranian offer, but was more interested in action. A senior official said Thursday that the offer, while inadequate, was a sign that American pressure is working.
"It was very telling that in the past 24 to 48 hours, the Iranians have started to try to deal again," said a senior administration official. "That indicates a great concern on their part.''
Other officials said, however, that the Iranian offer may have the effect of forestalling the action that the United States seeks next week at the International Atomic Energy Agency in Vienna. The agency has deplored Iran's lack of willingness to answer questions about its nuclear program but has taken no action.
The Bush administration wants the agency's 35-member board of governors to refer Iran's lack of cooperation to the United Nations Security Council, where sanctions and other forms of pressure might be considered.
On the other side, Germany and France argue that more pressure will make Iran less willing to consider curbs on its nuclear programs, which most experts regard as close to giving it the ability to make nuclear weapons.
Later this week, during a meeting in Geneva of top nuclear proliferation specialists from the major industrial countries, John R. Bolton, under secretary of state for nonproliferation affairs, will be trying to build a consensus to increase pressure on Iran.
The United States has tried and failed five times to get the votes to refer the matter to the Security Council, and Mr. Powell said last week that it would try again.
"We've been trying for the past five meetings to achieve that result," Mr. Bolton said in an interview before leaving for Geneva, referring to the effort to bring the matter before the Security Council. "We're going to try again in the sixth meeting. Whether or not that's possible, we've been unambiguous that we would make that push."
But European diplomats, asking not to be identified because the sensitive talks are continuing, expressed doubts that the referral would succeed. Some suggested instead that the United States give Iran one more chance to comply with the demands, with the clear understanding that failure will lead to sending the matter to the Security Council in November.
To some diplomats, the November meeting is critical because it would come after the American presidential election. Many experts say Iran is waiting to see the outcome of the race before deciding whether to negotiate with the Bush administration, even though Senator John F. Kerry has also taken a tough stance on the issue.
Administration officials said they had not yet been able to achieve a consensus on the board of governors. Normally the board takes action by consensus or not at all, which means that a strong dissenting minority can prevent it from acting.
Failing to get a consensus could signal a change of strategy for the administration, administration officials said. If there is no consensus, the administration may try to get a simple majority of the agency's board to send the issue to the Security Council. As a last resort, the administration may have to put the matter off until November.
"We're working it really hard right now," said a senior American official. "We may have to wait until next time, but we're really pushing hard to get this now." The official said that Mr. Powell had been on the telephone in the past week to press the issue.
If there is a yes-or-no vote, according to diplomats from countries involved in the talks, the United States might be able to get the votes of Australia, New Zealand, Canada, perhaps Japan and perhaps Spain and the Netherlands. The American strategy appears to be to line up enough votes that wavering countries might go along.