The chances of reviving the 2015 Iran nuclear deal are worse after indirect US-Iranian talks in Qatar’s capital of Doha that ended without progress, a senior US official told Reuters on Thursday. “The prospects for a deal after Doha are worse than they were before Doha and they will be getting worse by the day,” said the official on condition of anonymity. “You could describe Doha at best as treading water, at worst as moving backwards. But at this point treading water is for all practical purposes moving backwards,” he added. The official would not go into the details of the Doha talks, in wh…