Published April 07, 2015 FoxNews.com

Congressional critics of the Iran nuclear "deal" are worried Washington and Tehran can't even agree on what was in the accord struck last week, pointing to "dueling" fact sheets put out by each government.

"The bottom line is Iran has not agreed to a political framework that addresses all parameters of a comprehensive agreement, but rather has put out a dueling framework that contradicts the one put out by the United States," Sen. Mark Kirk, R-Ill., said in a written statement.

Kirk and other lawmakers are citing the stark differences between what Iranian and U.S. officials each say is in the deal, in questioning the Obama administration's sales pitch -- and demanding a say on any final agreement.

Senate Foreign Relations Committee Chairman Bob Corker, R-Tenn., told "Fox News Sunday" that Iran is touting "sort of the mirror image opposite of what's being reported here."

Harvard University's Belfer Center put out a translated version of Iran's fact sheet, which Kirk cited. Key differences include:

Sanctions

U.S.: The U.S. fact sheet says Iran will "receive sanctions relief, if it verifiably abides by its commitments" -- asserting sanctions relief would kick in only once conditions are met.

It says: "U.S. and E.U. nuclear-related sanctions will be suspended after the IAEA has verified that Iran has taken all of its key nuclear-related steps. If at any time Iran fails to fulfill its commitments, these sanctions will snap back into place."

Further, it says: "All past UN Security Council resolutions on the Iran nuclear issue will be lifted simultaneous with the completion, by Iran, of nuclear-related actions addressing all key concerns."

Iran: The Iran fact sheet, by contrast, says "all of the sanctions will be immediately removed after reaching a comprehensive agreement."

The translated fact sheet says: "According to the reached solutions, after the implementation of the Comprehensive Plan of Joint Action, all of the UN resolutions will be revoked and all of the multilateral economic and financial sanctions by the EU and the unilateral ones by the US will be annulled."

Centrifuges

U.S.: The U.S. statement says Iran won't use its advanced centrifuges for 10 years and can do "limited" research before that.

It says: "Iran will not use its IR-2, IR-4, IR-5, IR-6, or IR-8 models to produce enriched uranium for at least ten years. Iran will engage in limited research and development with its advanced centrifuges, according to a schedule and parameters which have been agreed to by the P5+1."

Iran: The Iran statement does not describe this research and development as "limited," but instead says: "Iran will continue its research and development on advanced machines and will continue the initiation and completion phases of the research and development process of IR-4, IR-5, IR-6, and IR-8 centrifuges during the 10 year period of the Comprehensive Plan for Joint Action."

Uranium stockpile

U.S.: The U.S. statement says "Iran has agreed to not enrich uranium over 3.67 percent for at least 15 years," and to "reduce its current stockpile of about 10,000 kg of low-enriched uranium (LEU) to 300 kg of 3.67 percent LEU for 15 years."

It also says Iran will only enrich uranium, using first-generation centrifuges, at its Natanz facility for 10 years.

Iran: Iran's statement does not appear to make the distinction between 10 and 15 years, saying: "The timeframe of the Comprehensive Plan of Joint Action regarding Iran's enrichment program will be 10 years." It then refers to the enrichment at Natanz occurring during this period.

Heavy water reactor

U.S.: The U.S. statement says the Arak heavy water reactor will be redesigned and rebuilt, and will not produce weapons grade plutonium. The statement says, "The original core of the reactor, which would have enabled the production of significant quantities of weapons-grade plutonium, will be destroyed or removed from the country."

Iran: The Iran statement says the Arak reactor "will remain" and will be enhanced and updated, including so it produces less plutonium. It does not mention the core being destroyed.

Corker, in questioning the discrepancies on Sunday, underscored the need for legislation he has co-sponsored that would demand congressional review of any nuclear deal.

President Obama opposes the bill, but in a troubling sign for the administration, even some in his own party support it. Most recently, Sen. Chuck Schumer, D-N.Y. -- who is Senate Democratic Leader Harry Reid's choice to succeed him after his retirement -- told Politico he supports the Corker bill.

Administration officials, meanwhile, have downplayed the discrepancies between how the U.S. and Iranian governments are portraying the framework -- which would be the basis for a final deal all sides are trying to reach by June 30.

An administration official said on a conference call last week that Iran's foreign minister will have to sell the deal just like the U.S. will.

Asked Monday about the discrepancy over the timing of sanctions relief, White House Press Secretary Josh Earnest acknowledged that the issue "still needs to be negotiated."

"There are still details about the phase-out, if you will, of the sanctions that have not yet been agreed to. And it is the strong view of the administration that it would not be wise, and it would not be in the interest of the international community, to simply take away sanctions ... on day one," Earnest said.