Iranian President Masoud Pezeshkian has thrown cold water on the possibility of dismantling its nuclear facilities, which Tehran maintains are only for peaceful domestic energy purposes.

But top US officials have called for just that. Starting earlier this month Secretary of State Marco Rubio said that Iran has to 'walk away' from uranium enrichment and long-range missile development, while Trump's special envoy to the Middle East Steve Witkoff just days ago went further, asserting that Iran's uranium enrichment facilities "have to be dismantled" for Washington to trust that it does not want nuclear arms.

Pezeshkian in the fresh comments blasted the demand as "unacceptable" and framed it as a matter of national sovereignty and independent development.

"The discussion that has been raised about dismantling Iran's entire nuclear facilities is unacceptable to us," the Iranian president said, adding that "Iran will not give up its peaceful nuclear rights."

Still, the country's Foreign Minister Abbas Araqchi acknowledged Sunday that negotiations with the United States in Oman had become "much more serious and frank" - which suggests positive momentum toward restoring a deal or at least an understanding on which to build a working relationship with Washington.

Araqchi in the comments given to Iran's state-run IRIB TV characterized "forward-moving" talks with the US over an array of complex nuclear-related issues.

This is despite last Thursday's provocative comments given to Breitbart wherein bluntly stated, "They cannot have centrifuges. They have to downblend all of their fuel that they have there and send it to a far-away place.”

"An enrichment program can never exist in the state of Iran ever again. That’s our red line," the US envoy asserted further.

“I just believe they have no choice” but to accept the White House position against enrichment, continued Witkoff. "Obviously, they can say no, and they can test President Trump, but I think that would be an unwise thing to do."

Iranian leadership has tended to brush off such maximalist demands, hoping instead that they can appeal to President Trump's pragmatic deal-making side and willingness to avoid war at all costs. Israel has long threatened preemptive attack on Iran if it believes Tehran is on the cusp of achieving a nuke. Trump has clearly distanced himself from these Israeli efforts to box him into a corner towards starting a new Middle East conflict.

President Pezeshkian meanwhile has continued stressing the "peaceful" purposes of the country's nuclear sites, which include the areas of radiopharmaceuticals, healthcare, agriculture, and industry.

"We are serious in the negotiations and seek an agreement. We hold talks because we want peace," he said. Iranian officials have of late complained that it's very hard to deal with the United States, given rotating administrations which have the capability to reverse key decisions of prior presidents.

Such was the case with the Obama-brokered JCPOA nuclear deal, which Trump unilaterally pulled out of in April 2018. It's as yet unclear the degree to which that original deal's terms will be restored or held to as part of the new ongoing talks.