The de facto mayor of the Ukrainian city of Slaviansk has said mediators from the Organisation for Security and Cooperation in Europe who are seeking the release of a group of detained observers had arrived in the city.
The self-proclaimed mayor, Vyacheslav Ponomaryov, told reporters he was heading into talks with the mediators.
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According to local reports, the man was found by friends in their accommodation in Val Thorens resort in the Alps on Sunday morning.