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.”

A third round of talks between Iran and the United States over Tehran’s nuclear activities concluded Saturday after several hours of negotiations, partly in writing, between senior officials and teams of technical experts from both sides.