Foreign Ministers from six major world powers began Monday a meeting with their Iranian counterpart, on the eve of a deadline in Vienna to agree a historic nuclear deal. Mohammed Javad Zarif and his counterparts from the US, China, Russia, Britain, France and Germany are seeking to nail down an accord curbing Iran’s nuclear programme in exchange for sanctions relief. The deal, aimed at ending a 13-year-old standoff over Iran’s nuclear programme, would build on a framework accord reached in April in Switzerland. Under that framework, Iran will reduce by more than two thirds it’s uranium centrifuges, which can make nuclear fuel but also form the core of a nuclear bomb and also reduce its uranium stockpiles and alter it’s Arak reactor. Tough issues in finalising the accord include working out the pace and timing of sanctions relief, Iran’s future capacities to develop nuclear equipment and enhanced UN access, including potential access to military bases in Iran. Iran denies wanting nuclear weapons, saying it’s activities are purely for peaceful purposes such as generating electricity and treating cancer patients.