Iran and the United States concluded 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 and the United States made “some but not conclusive progress” Friday in a fifth round of negotiations in Rome over Tehran’s rapidly advancing nuclear program, the talks’ Omani mediator said.

Iranian and U.S. delegations wrapped up a fifth round of talks in Rome on Friday and signs of some limited progress emerged in the negotiations aimed at resolving a decades-long dispute over Tehran's nuclear ambitions.