The Obama administration is hoping to rapidly secure a deal with Iran that would temporarily freeze the country's nuclear program and buy time for diplomats to try to hammer out a more comprehensive agreement restricting Tehran's future ability to seek atomic weapons, U.S. officials said Wednesday.

A proposal to be formally presented to Iran during negotiations this week would likely require the Islamic republic to suspend its production of enriched uranium and agree to additional curbs, concessions that would be rewarded with a modest, temporary easing of financial sanctions, according to a senior U.S. official knowledgeable about the plan.

While key details remained unclear, the proposal reveals the contours of a path that officials hope will lead to a resolution of the 10-year standoff over Iran's nuclear policies. The plan has the backing of five other world powers involved in the talks with Iran, and the key points have been shared with Iranian officials during technical talks, diplomats said.

The proposed freeze, if accepted, would be the first stage in a multiple-step process that could culminate in an agreement early next year on permanent limits to Iran's ability to produce the components of a nuclear bomb, the U.S. official said. Whether Iran would agree to the concessions will be a key topic during talks set to begin today in Geneva.

"What we're looking for now is a first phase, a first step, an initial understanding that stops Iran's nuclear program from moving forward for the first time in decades, and that potentially rolls part of it back," said the U.S. official in a briefing to journalists on the eve of the talks. The official, who spoke on the condition of anonymity to discuss sensitive diplomacy, said the United States and its allies were looking to "put time on the clock" by ensuring that Iran's nuclear program does not advance while the negotiations are underway.

The White House is under pressure to show substantial progress during this week's talks, as skeptics in Congress have threatened to impose harsh new financial sanctions on Iran even as the negotiations are under way. Administration officials met with key lawmakers last week urging them to delay any decisions on new sanctions until the first of the year.

The U.S. official in Geneva said an Iranian agreement to freeze its nuclear program would result in "limited, targeted and reversible" relief on some economic sanctions, for a limited period of perhaps six months. The easing of sanctions would be reversed if Iran failed to honor its commitments, or if there was no progress in the effort to achieve a broader nuclear agreement. The toughest sanctions affecting Iran's banking sector and oil exports would not be lifted until the final stage of the process, Western officials said.

Diplomats from Iran and a bloc of six world powers are meeting in Geneva for the second time since the June election that swept moderate cleric Hassan Rouhani into power on a promise to end Iran's diplomatic isolation. Iran's newly appointed foreign minister, Mohammad Javad Zarif, told a French broadcaster Tuesday that he believed a deal could be reached to win sanctions relief for Iran while easing international concerns about Iran's nuclear intentions.

"I believe it is even possible to reach that agreement this week," Zarif said. He added that "it is not a disaster" if a breakthrough fails to occur during the current round of talks. An earlier session three weeks ago was described by all sides as serious and substantive, but produced no tangible results.

Both Rouhani and President Barack Obama face pressure from conservatives who are deeply skeptical of any rapprochement with the other side. Hard-liners in Iran staged rallies in the capital Monday in which thousands of demonstrators chanted "Death to America" to signal their opposition to any thawing of relations with Washington.

Obama's overtures to Iran have drawn intense skepticism from a broad spectrum of political conservatives, Iran hawks and some pro-Israel groups, as well as key allies Saudi Arabia and Israel. Some congressional opponents have threatened to push for legislation that would block the administration from granting even temporary relief from sanctions unless Iran suspends all work at its nuclear and ballistic missiles facilities.

Israeli Prime Minister Benjamin Netanyahu, speaking at a joint news conference Wednesday with Secretary of State John Kerry, warned against a "partial deal" that would stop short of the full dismantlement of Iran's nuclear program.

"I believe that as long as they continue their goal to enrich uranium to get nuclear weapons, the pressure should be maintained and even increased because they're increasing enrichment," Netanyahu said.

Kerry said afterward that the Obama administration would "remember our friends and their interests" as talks with Iran proceed. But he also suggested that a deal could be achieved that would allow Iran to pursue peaceful nuclear energy under the same kinds of restrictions and oversight that other states without nuclear weapons have accepted.

"Our hope is that Iran will understand that this is a simple obligation: Show the world that you are pursuing a peaceful program," Kerry said. "It's not that hard."