Negotiations between Iran and the United States over Tehran’s rapidly advancing nuclear program are set to return to the secluded sultanate of Oman.

The Trump administration is prepared to allow Iran to have a civil nuclear program that relies exclusively on imported nuclear fuel, Secretary of State Marco Rubio said, outlining a possible compromise with Tehran aimed at preventing it from building a nuclear weapon.

Iran and U.S. negotiate nuclear program limits in exchange for sanctions relief, with China and Russia support.