An earlier version of this article incorrectly reported that a U.S. intelligence official had described regime collapse as a goal of U.S. and other sanctions against Iran. An updated version clarifies the official’s remarks.

The Obama administration sees economic sanctions against Iran as building public discontent that will help compel the government to abandon an alleged nuclear weapons program, according to a senior U.S. intelligence official.

In addition to influencing Iranian leaders directly, the official said, “another option here is that [sanctions] will create hate and discontent at the street level so that the Iranian leaders realize that they need to change their ways.”

The intelligence official’s remarks pointed to what has long been an unstated reality of sanctions: Although designed to pressure a government to change its policies, they often impose broad hardships on a population. The official spoke this week on the condition of anonymity to discuss internal administration assessments.

The comments came as the administration readies punitive new sanctions that affect Iran’s central bank and the European Union moves toward strict curbs on Iranian oil imports.

A senior administration official, speaking separately, acknowledged that public discontent was a likely result of more punitive sanctions against Iran’s already faltering economy, but said that is not the direct intent.

“We have a policy that is rooted in the notion that you need to supply sufficient pressure to compel [the government] to change behavior as it’s related to their nuclear program,” this official said.

“The question is whether people in the government feel pressure from the fact that there’s public discontent,” the official said, “versus whether the sanctions themselves are intended to collapse the regime.”

A Western diplomat familiar with the policy said that it was “introducing in the cost-benefit analysis a new parameter in the calculus” of the Iranian government. “To the extent we have done that, it is not because we want to collapse the government. It is because we want the Iranian government to understand that is a possible cost in continuing the way it is,” the diplomat said, speaking on the condition of anonymity to describe the intent of the policy.

Dennis B. Ross, who managed Iran policy on the National Security Council staff until November, said, “The sanctions all along have been designed to put the Iranians in a position where they had to make a choice, and if they did not make a choice, that they realize the price for not doing so would be high. . . . They are absorbing a price now that they themselves do not want to absorb.”

President Mahmoud Ahmadinejad dismissed international concerns about an Iranian nuclear weapon this week, calling it “a joke.”

“It’s something to laugh at,” Ahmadinejad said during a visit to Venezuela, the Associated Press reported from Caracas. “It’s clear they’re afraid of our development.”

Obama’s Iran policy, which began with an attempt to engage that nation’s civilian and clerical leadership, has come under withering criticism from Republican presidential candidates eager to cast him as weak abroad. The GOP front-runner, former Massachusetts governor Mitt Romney, has said that “if we reelect Barack Obama, Iran will have a nuclear weapon.”

The GOP candidates have accused Obama of being insufficiently attuned to the immediacy of the Iranian nuclear threat. The intelligence official, however, said the intelligence community stands by its controversial 2007 conclusion that Iranian leaders have not decided whether to build a nuclear bomb.

As the intelligence community thinks through the Iran situation, the official said, it realizes that the sanctions-induced pressure has a possible downside.

“It could have the opposite effect from what’s intended,” he said, “and impel the Iranian leader to decide, ‘We’re going to build that nuclear weapon.’ We’ve thought of that.”

Although not advocating such a course, the official said that obtaining a nuclear weapon “actually might temper [Iran’s] behavior,” enabling the United States to warn that it, too, has nuclear weapons. “It puts them on an even playing field, where they might not want to be,” he said of the Iranians.

Although Obama has declined to rule out a military strike against Iran’s nuclear sites to prevent the Islamic Republic from building a nuclear weapon, the president has emphasized international diplomacy, which has helped build broad allied support for stringent economic sanctions against Iranian officials, key businesses and now the nation’s central bank.

Those measures are already producing economic hardship in Iran and pressure on the Iranian government, which has responded with threats to close key shipping lanes vital to international oil exports.

Although Iran has continued to develop its nuclear infrastructure — including a recently revealed second uranium-enrichment facility — the “pause” in the nation’s direct march toward a weapon continues, the intelligence official said.

“Our belief is that they are reserving judgement on whether to continue with key steps they haven’t taken regarding nuclear weapons,” he said.

“It’s not a technical problem,” he said, adding that Iran already has the capability to build a bomb.

Israel, the intelligence official said, has “a different opinion. They think [Iran] has already made the decision.

The possibility that Israel will take action on its own to thwart Iran’s nuclear ambitions is “a very serious concern,” the intelligence official said. If the Israelis attack, he said, “it is very clear that Iran will retaliate” against Israel and ultimately hold the United States responsible.

“In the end,” the intelligence official said of Israel, “they’re a sovereign country. . . . How much notice they might give us, I don’t know.”

The International Atomic Energy Agency’s latest report on Iran, in November, cited evidence suggesting a resumption of weapons research after 2004, including work on triggering devices as recent as 2007. Officials for the nuclear agency have acknowledged in interviews that the evidence is ambiguous.

“The information indicates that Iran has carried out activities relevant to the development of a nuclear explosive device,” the nuclear agency said in its report. “The information also indicates that prior to the end of 2003, these activities took place under a structured programme, and that some activities may still be ongoing.”

Although different countries and agencies are looking at the same evidence, U.S. officials have tended to be conservative in their interpretation, in what some of the European counterparts regard as a reaction to the U.S. intelligence missteps before the 2003 U.S.-led invasion of Iraq.

“It is clear to everyone that, early in the last decade, a decision was made by Iran to close the ‘formal’ program,” said one European diplomat involved in internal IAEA discussions about Iran. “The question is whether the work is still being carried on, and to what end. It is harder to pin that down with exactitude.”

Staff writer Joby Warrick contributed to this report.