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.

The U.S. and Iran ended talks with "some but not conclusive progress" on nuclear negotiations, according to an Omani mediator. But the countries still appear far apart, with the U.S. saying Iran cannot be allowed to enrich uranium for civilian use.

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.