Leaders from the United States and Iran painted a positive but cautious picture of talks between the nations over Iran’s nuclear program Saturday, after the third phase of the discussions wrapped up in Oman.

Washington opposes Tehran’s insistence on retaining the ability to enrich uranium, but U.S. calls latest round “productive.”

MUSCAT, Oman —Iran and the United States held their first technical-level talks on Tehran’s rapidly advancing nuclear program Saturday, a more complex phase of their high-stakes negotiations.