French Foreign Minister Laurent Fabius will travel to Vienna on Sunday to assess the state of talks between world powers and Iran over curbs on the Islamic republic's nuclear programme, a diplomatic source in Paris said. Fabius and officials in the P5+1 group comprising the United States, Russia, Britain, France, Germany and China will "evaluate the situation" in the talks, which aim to reach a definitive accord with Iran by July 20, according to the source. The source did **t say which other foreign ministers would attend. Final negotiations to secure a historic accord to guarantee the peaceful nature of Iran's nuclear programme in exchange for the lifting of sanctions against Tehran began on July 3 in Vienna.