"Any final arrangement must set a framework for peace, stability, and prosperity in the Middle East -- meaning that Iran must stop and eliminate its nuclear enrichment and weaponization program," Witkoff said on X.

The previous day, he appeared to stop short of calling for a complete dismantling of Iran's nuclear program, saying in a Fox News interview that "this is going to be much about verification on the enrichment program."

"They do not need to enrich past 3.67 percent," the real estate magnate said, referencing the maximum level allowed under the prior nuclear agreement that Trump exited during his first term, in 2018.

The multi-party 2015 deal that Trump abandoned aimed to make it practically impossible for Iran to build an atomic bomb, while at the same time allowing it to pursue a civil nuclear program.

The latest International Atomic Energy Agency report said Iran had an estimated 274.8 kilograms of uranium enriched to 60 percent, nearing the weapons grade of 90 percent.

White House Press Secretary Karoline Leavitt meanwhile told journalists Tuesday that President Donald Trump had spoken with Oman's Sultan Haitham bin Tariq, thanking him for hosting talks on a deal with Tehran.

Trump has threatened to strike Iran's nuclear facilities if no deal was reached, calling Iranian authorities "radicals" who should not possess nuclear weapons.

Tehran denies seeking an atomic bomb, saying its nuclear program is for peaceful purposes, especially energy production.