The United States and Iran have begun a third round of nuclear talks, entering what experts describe as a more difficult phase of technical negotiations this weekend as Washington lays out its conditions.

Iran and the United States are preparing to start in-depth negotiations in Oman over Tehran’s rapidly advancing nuclear program, talks that likely will hinge on the Islamic Republic’s enrichment of ur

The U.S. and Iran concluded on Saturday the third round of nuclear talks and agreed to meet again on May 3, said Omani foreign minister Badr Al-Busaidi, who is mediating between the parties. Why it matters: The talks in Muscat on Saturday were the first time the parties dived into the technical details of a possible nuclear deal,