President Donald Trump said he would hold a meeting in the White House Situation Room on Friday to make a “final determination” on a proposed agreement with Iran.
In a post on Truth Social, Mr Trump said the deal, if agreed, would reopen the Strait of Hormuz immediately and permanently bar Tehran from obtaining a nuclear weapon.
“Iran must agree that they will never have a nuclear weapon or bomb. The Hormuz Strait must be immediately open, no tolls, for unrestricted shipping traffic, in both directions,” he wrote.
Mr Trump said the US had removed numerous naval mines from the strait and that Iran would be responsible for clearing any remaining explosives.
“No money will be exchanged, until further notice. Other items, of far less importance, have been agreed to,” he said.
He added that ships stranded in the strait because of what he described as an “unprecedented naval blockade” could now begin “heading home”.
The President also said the US, working alongside Iran and the International Atomic Energy Agency, would oversee the destruction of enriched nuclear material buried underground at Iranian facilities damaged in US strikes.
Later on Friday, Iran played down the prospect of a deal with the US.
Foreign Minister Abbas Araghchi said clinching an agreement would require an end to the "excessive approach and changing and contradictory positions" of the Americans.
The pro-regime Fars news agency disputed Mr Trump's description of the deal, saying it included a key Iranian demand for $12 billion in frozen assets.
Citing informed sources, it also denied there was any agreement to remove nuclear materials.
The development comes after days of both sides signalling that a tentative agreement had been reached to extend the ceasefire and bring an end to the conflict that began in February.
On Wednesday, Mr Trump said Iran was eager to reach a deal but that it had not yet met US expectations.
He also warned that military action against Tehran could resume if negotiations failed.
