The president told Israel of his decision earlier in April, according to the report, prompting Prime Minister Benjamin Netanyahu's Washington visit.
Steve Witkoff said that the US was "open to compromise" within Iran nuclear talks, only to backtrack his comments and call for the elimination of Iran's nuclear enrichment and weaponization program.
Iran and the US are due to hold a second round of talks in Oman on Saturday over Tehran's escalating nuclear program, with President Donald Trump threatening military action if there is no deal.
Sources: Simply destroying Iran’s Fordow nuke facility 'worthless,' diluting uranium gains limited time.
Khamenei said Tehran retains a "very pessimistic" overall view of the US and should not tie its national affairs to nuclear negotiations.
Steve Witkoff, Trump’s envoy and the US representative in nuclear talks with Iran’s foreign minister, to Fox: "Iran must not possess nuclear weapons, and it should not enrich uranium beyond 3.67%."
Trump, who has threatened military action if no deal is reached on halting Iran's nuclear program, told reporters aboard Air Force One that he met with advisers on Iran and expected a quick decision.
The US sanctioned five Iranian entities for nuclear activity, just days before planned nuclear talks in Oman, as Trump warns of consequences if talks fail.
Iranians are cautiously hopeful ahead of US nuclear talks, as markets rise and the rial strengthens, but fears of failure and conflict linger.
Iran expresses skepticism over upcoming US talks on its nuclear program, insisting on indirect negotiations and demanding concrete gestures before direct discussions.