Nuclear talks with Iran begin in ViennaListen /
Negotiations on the future of Iran's nuclear programme are due to start at the United Nations in Vienna on Tuesday.
Six world powers will join Iran for talks which are aimed at curbing elements of the country's nuclear programme in exchange for a gradual end to sanctions.
Western powers fear the programme is intended to create nuclear weapons capabilities, an accusation that Iran denies.
A November 2013 interim deal between Iran and the five permanent UN Security Council members plus Germany, the so-called G5+1 took nearly two months to agree.
The agreement is valid for six months and can be renewed.
Iran agreed to suspend its most sensitive nuclear activity in exchange for a limited easing of Western sanctions that are reportedly damaging its oil-reliant economy.
The Vienna talks are aimed at laying the ground work for a definitive agreement.
Jocelyne Sambira, United Nations.