Former national security adviser Susan Rice on Sunday strongly criticized the preliminary agreement between the Trump administration and Iran, describing it as 'flimsy' and a strategic blunder.

Rice, who served as national security adviser when the 2015 Iran nuclear deal was negotiated, argued that the United States has made too many concessions in the current pact, leading to a detrimental outcome.

"It's egregious, Jon, because so many concessions were granted up front in this flimsy, two-page memorandum of understanding that wouldn't normally and shouldn't have been granted until after there was not only a full comprehensive deal to at least deal with their nuclear program, but also that those provisions that were negotiated had been agreed," Rice told ABC News' "This Week" co-anchor Jonathan Karl.

The current agreement, according to Rice, allows Iran to sell all of its oil unimpeded and access tens of billions of dollars in frozen assets within 60 days, contingent on the memorandum's implementation. She contrasted this with the Obama-era deal, where such funds could only be used for humanitarian purposes like food and medicine.

Rice pointed out that the most sensitive nuclear issues are not yet definitively agreed upon in the current text. While the memorandum reaffirms Iran's commitment not to procure or develop nuclear weapons, it lacks definitive terms on enrichment limits and dealing with the country's stockpile of highly enriched uranium.

The 2015 Joint Comprehensive Plan of Action, negotiated over 18 months, required Iran to make significant concessions on its nuclear program, including not enriching bomb-grade uranium for 15 years, dismantling two-thirds of its centrifuges, surrendering 98% of its uranium stockpile, and allowing UN inspectors oversight.

Under the new agreement, the disposition of enriched material will be resolved through a mutually agreed mechanism, with the minimum methodology being down-blending on-site under International Atomic Energy Agency supervision. Discussions on enrichment and other nuclear-related matters are also planned.

Rice expressed concern that Iran could use unfettered access to its frozen assets to re-arm itself, a stark contrast to the restrictions imposed by the previous agreement.