Iran, U.S. conclude 4th round of negotiations over Tehran's nuclear program in Oman

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 half a century of enmity. Since the nuclear deal’s collapse in 2018 with Trump’s unilateral withdrawal of the U.S. from the accord, Iran has abandoned all limits on its program and enriched uranium to up to 60% purity — a short, technical step from weapons-grade levels. Trump said he wrote the letter on March 5, which made it to Iran via an Emirati diplomat on March 12 — putting the deadline in theory as Monday when Trump takes off from Washington for his trip to Saudi Arabia, Qatar and the United Arab Emirates.