Iran and the United States are set to begin a fifth round of high-stakes nuclear talks in Rome on Friday amid growing skepticism in Tehran about the chances of a deal as Washington hardens its position.

Iran said it’s “time to decide” ahead of Friday’s nuclear talks with the US, with the main sticking point being whether Tehran will be able to continue enriching uranium.

Iranian and U.S. negotiators will resume talks on Friday in Rome to resolve a decades-long dispute over Tehran's nuclear ambitions, despite Iran's supreme leader warning that clinching a new deal might be insurmountable amid clashing red lines.