The United States faces a tough, messy battle if it uses a threat to trigger a return of all United Nations sanctions on Iran as leverage to get the 15-member Security Council to extend and strengthen an arms embargo on Tehran, diplomats said. Washington has shared its strategy, confirmed by a U.S. official speaking on condition of anonymity, with Britain, France and Germany, who are council members and parties to the 2015 deal between Iran and world powers that prevents Tehran from developing nuclear weapons in exchange for sanctions relief.
