VIENNA, Rajab 17, 1435, May 16, 2014, SPA -- An ambitious round of nuclear talks between Iran and six world powers ended Friday with serious setbacks, with a senior Iranian official saying the two sides are at odds on several key issues, AP reported. Both sides were supposed to start drafting a final agreement that the six hope will constrain Iran's nuclear program. Tehran in turn is seeking a full lifting of sanctions. But Iranian Deputy Foreign Minister Abbas Araghchi told Iranian media Friday that differences were too big to start the drafting process. He gave no immediate details beyond saying that both sides were apart on several issues. "There was no tangible progress in this round of the talks," Araghchi said. "We will have one or two more rounds of talks in June. Talks will continue." Talks began Feb. 18 on a comprehensive deal meant to constrain Iranian nuclear work that can make such arms in exchange for full sanctions relief on Tehran's economy. Araghchi said there was still hope a final deal can be reached before July 20, the target date for a comprehensive deal. Iran denies any interest in nuclear weapons, saying its enrichment program is meant only to make reactor fuel. But because the technology can also create weapons-grade uranium for warheads depending on the level of enrichment, Washington and its allies want strict constraints on its size and scope. The dispute over enrichment surfaced less than two months before the July 20 target date for a deal and follows encouraging signs of progress on less contentious issues in earlier rounds that had raised hopes that a pact could be sealed by then. Diplomats say there is a tentative agreement to re-engineer a partially built reactor so that it would produce less waste plutonium - material that also can be used for the core of a nuclear weapon. -- SPA 20:21 LOCAL TIME 17:21 GMT www.spa.gov.sa/1233204