Israel is reportedly urging its Western allies to reject an expected proposal to limit Iran’s nuclear program in exchange for limited relief from crippling economic sanctions.

“Israel in the last few hours has learned that a proposal will be brought before the P5+1 in Geneva in which Iran will cease all enrichment at 20 percent and slow down work on the heavy water reactor in Arak, and will receive in return the easing of sanctions,” an Israeli official told AFP Wednesday, speaking on condition of anonymity.

“Israel thinks this is a bad deal and will oppose it strongly,” the official added.

A senior US official, speaking to reporters on Wednesday said both sides are coming to the table in Geneva Thursday with an understanding of what they want from each other as a “first step” — and what they are willing to give in return. She, too, asked for anonymity as a condition for participation in her briefing.

She said the six world powers — the US, UK, France, Russia, China and Germany — are ready to offer “limited, targeted and reversible” sanctions relief in response to agreement by Iran to start rolling back activities that could be used to make weapons.

But in a nod to skeptics in Congress, she emphasized that any economic relief given Iran can be canceled, should Tehran renege on commitments it makes in Geneva. And she said the six powers were looking to test the durability of any initial nuclear limits Iran agreed to by waiting — possibly for as long as six months — after such agreement before any sanctions relief kicked in.

Another official from one of the delegations negotiating with Iran said easing core sanctions on Iran’s oil industry and finance sectors is not on offer unless Tehran makes sweeping concessions — something it is not likely to do at this point. He also demanded anonymity because he was not authorized to discuss negotiating points.

The Israeli official told AFP, “Israel’s assessment is that the P5+1 is in a position of strength. The sanctions are hurting Iran, Iran is feeling the pressure and the P5+1 has the capability to compel Iran to end all enrichment and to stop construction of the facility in Arak.”

In Tehran, Iran’s Revolutionary Guard leaders have been mollified somewhat for now by supreme leader Ayatollah Ali Khamenei’s suggestion that he will give President Hassan Rouhani only a limited time to negotiate an end to the sanctions. Underscoring the support that the hard-liners enjoy in Tehran, tens of thousands marked Monday’s anniversary of the 1979 storming of the US Embassy with chants of “Death to America!”

The Associated Press contributed to this report.