The talks with the U.S. again will be mediated by Oman. The sultanate has hosted two rounds of talks in Oman's capital, Muscat, and one round at its embassy in Rome.
The talks seek to limit Iran's nuclear program in exchange for the lifting of some of the crushing economic sanctions the U.S. has imposed on the Islamic Republic closing in on a half-century of enmity.
U.S. President Donald Trump has repeatedly threatened to unleash airstrikes targeting Iran's program if a deal isn't reached. Iranian officials increasingly warn that they could pursue a nuclear weapon with their stockpile of uranium enriched to near weapons-grade levels.