WASHINGTON — Top American nuclear negotiator Wendy Sherman on Thursday sought to assure the Senate Committee on Banking, Housing and Urban Affairs that the interim deal reached in Geneva last month between P5+1 states and Iran was effective, and that sanctions relief through the deal will be minimal. But Sherman used conditional language that appeared to indicate a reluctance to commit that the ultimate level of sanctions relief, offered to Iran under the deal for partially freezing its rogue nuclear program, would indeed be held to the previously stated $6-7 billion.

“There have been some [reports] that have incorrectly represented the limited relief as being far more,” Sherman told senators. “So, let me reiterate. The total relief envisioned in the JPA (Joint Plan of Action agreed in Geneva) amounts to between $6-7 billion — nowhere near the $20 or $40 billion that some have reported. The total relief for Iran envisioned in the JPA would be a modest fraction of the approximately $100 billion in foreign exchange holdings that are inaccessible or restricted because of our ongoing sanctions pressure.”

The undersecretary of state for political affairs’ use of “envisioned” and “would be,” rather than a simple statement, appeared to suggest a wariness to commit to the figure.

Sherman, who is likely to participate in an addition round of political negotiations prior to the start date of the interim, told the senators its implementation will begin “in the coming weeks.” Although it was suggested in Geneva last month that an agreement had been reached, it later emerged that numerous “technical details” had not been resolved.

On Wednesday evening, speaking to an event celebrating the centennial of the American Jewish Joint Distribution Committee, Treasury Secretary Jack Lew also said that the sanctions relief would total approximately $7 billion. Recent reports in Israeli media have suggested that ultimately, the total sanctions relief offered in the JPA will be closer to $20 billion, and have also asserted that various “under the table” concessions were made to Iran in Geneva.

Sherman was cautious in her description of the planned comprehensive solution to the Iranian crisis, describing its goal as to “resolve the international community’s concerns with Iran’s nuclear program” rather than denying Iran the capacity to build a nuclear bomb. A final deal is supposed to be finalized in talks over the six months following implementation of the JPA.

Sherman did not say that the implementation of the JPA or the final deal would eliminate Iran’s capacity to build a nuclear weapon, but rather that “taken together, these measures will prevent Iran from enhancing its ability to create a nuclear weapon and increase the confidence in our ability to detect any move towards nuclear break-out or diversion of material towards a covert program.”

Sherman detailed the Iranian obligations during the JPA phase, including to roll back or neutralize key aspects of its program, to cease all enrichment over five percent, to dismantle piping at Fordo and Natanz that is used to more efficiently enrich uranium over five percent, and to neutralize its entire 20 percent stockpile of enriched uranium hexafluoride by diluting it to a lower level of enriched uranium hexafluoride or converting it to oxide for fuel for the Tehran Research Reactor.

In addition, according to Sherman, Iran may not advance work on the plutonium track through the Arak heavy water plant. Tehran will not be able to commission the heavy water reactor under construction. It may not transfer fuel or heavy water to the reactor site, test additional fuel or produce more fuel for the reactor. It may not install remaining components for the reactor. And it may not construct a facility for reprocessing spent fuel. These are all steps that, according to Sherman, “freeze the timeline for beginning operations at the Arak reactor and halts progress on any plutonium pathway to a weapon.”

Sherman said that the monitoring imposed under the JPA includes daily access by International Atomic Energy Agency (IAEA) inspectors to the facilities at Natanz and Fordo and “more frequent” access to the Arak reactor. Beyond those sites, Sherman said that Iran must allow International Atomic Energy Agency (IAEA) inspectors access to sites related to centrifuge assembly and production of centrifuge rotors, to uranium mines and mills, as well as providing design information for the Arak heavy water reactor.

Sherman and other Obama administration emissaries have had trouble getting Senate hawks to work with the administration in stepping down from a bid to place additional sanctions on Iran despite the JPA. Amid reports that the Democratic leadership will ensure that such a bill will not surface until the Senate returns from its recess in January 2014, Republican senators have remained critical of the interim deal.

Israel’s Haaretz daily claimed on Wednesday that US officials have conceded to Israel that the sanctions relief might turn out to be worth over $20 billion. The Yedioth Ahronoth daily on Thursday claimed that Iran had secured various concessions from the P5+1, mostly relating to the Arak facility, that had been kept secret from Israel.

It said a team led by Prime Minister Benjamin Netanyahu’s National Security Adviser Yossi Cohen, currently in the US, would be raising this and other concerns in talks with US officials. Netanyahu has condemned the Geneva deal as a “historic mistake,” and reiterated in comments this week that Iran must be denied all enrichment capability, and stripped of its entire “military nuclear” capacity, under a permanent deal.

During the hearing, Senator Bob Corker (R-TN), ranking member of the Foreign Relations Committee, complained that the interim agreement requires “no sacrifice” of Iran and that the sanctions relief being offered by the US risks creating “a rush” to do business with Iran.

“Once you begin loosening sanctions, and people begin to see that Iran is now going to become not a rogue country but part of the international community there is a rush to do business with them. And I think that’s why we’re all concerned that we did an interim deal that has no sacrifice on their part whatsoever,” Corker admonished Sherman. “Obviously, we’re disappointed but hopeful that somehow you can put the genie back in the bottle and end up with some type of agreement that averts warfare. Because of all of us do want this to succeed. We just don’t know how we get there with an interim deal framed in this way.”