WASHINGTON -- Iran will receive approximately $55 billion in sanctions relief once the nuclear deal is implemented, said Treasury Secretary Jack Lew -- a fraction of the $150 billion that critics of the agreement have claimed will go to the country.

There is a lot of discussion out there that Iran is going to somehow get $150 billion as soon as sanctions are lifted. That is incorrect, said Lew, speaking at a breakfast hosted by the Christian Science Monitor on Wednesday. He explained that Iran will not be able to access much of its money that has been locked up overseas due to sanctions because the money has already been committed elsewhere.

Last week, Lew told a group of senators that over $20 billion of Irans frozen assets has already been committed to infrastructure projects with China, and that Iran owes an additional "tens of billions" of dollars on nonperforming loans to its energy and banking sectors.

On Wednesday, Lew estimated that Irans demand for domestic investment surpasses $500 billion, and that it will cost between $100 billion and $200 billion to restore production levels in its oil and gas sector.

I have never argued that a penny cant be put to a malign purpose, Lew said. But this is not going to change the shape of Irans resources for good or bad purposes.

Lews remarks came just before he headed to Capitol Hill, where he, along with State Secretary John Kerry and Energy Secretary Ernest Moniz, will brief lawmakers on the merits of the nuclear accord for the third time since it was finalized on July 14.

Members of Congress have until mid-September to review the nuclear agreement negotiated between Iran, the U.S. and five world powers, and vote on the deal. If a vote against the deal has the support of two-thirds of the House and the Senate, the president will lose his ability to temporarily waive some sanctions against Iran, which would likely sink the agreement.

On Wednesday, Lew said there was growing support in Congress from the lawmakers who are listening to the administrations arguments on the merits of the accord. He declined to share the number of lawmakers he would include in that group, but has showed growing frustration with some members staunch opposition to the nuclear deal.

During Lews last congressional testimony on Tuesday, several lawmakers used the bulk of their allotted time to state their problems with the agreement, leaving little time for Lew, Kerry and Moniz to answer. If we got a minute or two to respond, it might actually be helpful for people who want to understand the agreement, Lew said at one point during the four-hour-long briefing.

Despite the administrations efforts to win over Congress, theres a sizable group of lawmakers who are immovable in their conviction that the agreement guarantees Iran nuclear weapons and funding to ramp up its support for Hamas, Hezbollah and the Houthis. Within this group, several members have floated the idea of passing new sanctions against Iran, targeting its human rights abuses and support for terrorist groups.

While the nuclear deal does not prohibit the implementation of new sanctions that are unrelated to Irans nuclear program, it does include a clause that commits all parties to refrain from any action inconsistent with the letter, spirit and intent of this [agreement] that would undermine its successful implementation." Iran has already told the U.N. that it would reconsider its own commitments under the deal if it were hit with new sanctions similar or identical to those already in place, even if they were imposed for non-nuclear reasons.

This does not mean that the Obama administration has precluded itself entirely from imposing new sanctions on Iran, Lew insisted. We reserve all of our rights to impose sanctions based on acts of terrorism, based on human rights violations, and based on regional destabilization, he said. What I think does present an issue is if either Congress or [the executive] take all of the sanctions that are being lifted, put a new label on them, and say they are being reimposed.