Washington | US Secretary of State Marco Rubio was asked in a Fox News interview about Iran's latest proposal, which would postpone discussions on its nuclear programme but end its chokehold on the Strait of Hormuz if the US lifts its blockade and ends the war.

"There's no doubt in my mind that at some point in the future, if this radical clerical regime remains in charge in Iran, they will decide they want a nuclear weapon," Rubio said.

"That fundamental issue still has to be confronted," he said. "That still remains the core issue here." Asked if he thinks the Iranians are serious about a deal, Rubio said they are skilled negotiators looking to buy time.

"We can't let them get away with it," Rubio said. "We have to ensure that any deal that is made, any agreement that is made, is one that definitively prevents them from sprinting towards a nuclear weapon at any point."