Iran and the United States have started in-depth negotiations in Oman over Tehran’s rapidly advancing nuclear program, talks that likely will hinge on the Islamic Republic’s enrichment of uranium.

Tensions have remained high since Trump withdrew from the 2015 nuclear agreement in 2018, prompting a series of escalations. Iran has since abandoned all limits on its nuclear programme, and enriches uranium to up to 60 percent purity – near weapons-grade levels of 90 percent.