World powers, Iran, U.S. launch indirect talks to revive nuclear deal By Francois Murphy, Parisa Hafezi and John Irish Reuters VIENNA (Reuters) -European intermediaries began shuttling between Iranian and U.S. officials in Vienna on Tuesday as they sought to bring both countries back into full compliance with the 2015 nuclear deal that Washington abandoned three years ago. Iran has steadily overstepped the accord's limits on its nuclear programme in response to the United States' withdrawal from the accord under then-President Donald Trump in 2018 and its reimposition of sanctions that have crippled the Islamic Republic's economy. While Tehran has repeatedly rebuffed "direct and indirect negotiations" with its old foe, Washington said on Monday it expected the discussions to be difficult. Neither side expected any early breakthrough.