Neither Washington nor Tehran say they expect any quick breakthroughs from the talks Reuters April 07, 2021 Iranian Deputy at Ministry of Foreign Affairs Abbas Araghchi arrives at a meeting of the JCPOA Joint Commission, in Vienna, Austria, April 6, 2021. REUTERS VIENNA: Iran and world powers held what they described as “constructive” talks on Tuesday and agreed to form working groups to discuss the sanctions Washington might lift and the nuclear curbs Tehran might observe as they try to revive the 2015 nuclear deal. European intermediaries have started shuttling between Iranian and U.S. officials in Vienna as they seek to bring both countries back into compliance with the accord, which lifted sanctions on Iran in return for curbs to its nuclear programme.