A meeting of the remaining partners in the Iranian nuclear deal produced some progress but not enough to satisfy Tehran's demands, a senior Iranian official said Friday, offering little prospect for now of the country backing away from a move to surpass a uranium stockpile threshold that could doom the agreement. Abbas Araghchi, Iran's deputy foreign minister, said after meeting with senior officials from Britain, Germany, France, China, Russia and the European Union that a complex barter-type system set up to keep trade with Iran afloat is now active. Araghchi described the meeting in Vienna, a regular quarterly gathering of signatories to the 2015 accord, as positive and constructive.