Iran and world powers were nursing their wounds on Saturday after a bruising round of nuclear talks, but diplomats and experts remain hopeful a historic deal can still be struck by a July 20 deadline. "The gaps were too large to begin drafting the text," said Iran's chief negotiator Abbas Araqchi, adding that "** tangible progress" had been made. The aim of the sought-after accord is to reduce the scale of Iran's nuclear activities, easing fears it is seeking to construct a bomb, in return for a lifting of all sanctions. At the heart of the debate is uranium enrichment, which can provide nuclear fuel but also the fissile core of a nuclear bomb.