Iran for the first time on Monday, June 18, gave a point-by-point response to an international proposal on halting its 20% enrichment activities. But international diplomats said the presentation, replete with PowerPoint slides, if anything only made more daunting the diplomatic challenge of trying to narrow the yawning gaps between the two sides in the near term.

“We had an intense and tough exchange of views today,” Michael Mann, spokesman for European Union foreign policy chief and lead international negotiator Catherine Ashton, told journalists at the conclusion of the first day of international Iran nuclear negotiations in Moscow Monday.

The Iranians “responded to our package of proposals from Baghdad but, in doing so, brought up lots of questions and well-known positions, including past grievances,” Mann said. “We agreed to reflect overnight on each others’ positions.”

“It’s not enough, it’s not close to enough,” a diplomat at the talks said later on condition of anonymity, and that the lengthy Iranian presentations Monday did not strike him as signaling Iranian seriousness about negotiations on confidence-building steps.