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.

Mediator Oman says Iran and the United States made “some but not conclusive progress” in a fifth round of negotiations in Rome over Tehran’s rapidly advancing nuclear program

The United States and Iran are set to hold a fifth round of talks over the latter's nuclear program in Rome on May 23, and the stakes could hardly be higher.