MARIUPOL/SLAVIANSK, Ukraine, Rajab 11, 1435, May 10, 2014, SPA -- Acting Ukrainian President Oleksander Turchinov told eastern regions gripped by a pro-Russian uprising that they would be courting catastrophe if they voted "yes" in a separatist referendum on Sunday, Reuters reported. The vote, organised on an ad hoc basis with no clear control of authenticity of ballot papers or voter lists, could determine if the Western-backed Kiev government and pro-Russian eastern regions find a compromise, or whether Ukraine slides into civil war. Violence has grown along with the bitter rhetoric in the regions of Donetsk and Luhansk, where the vote will take place. "A dreadful terror is in train with the support of a large part of the local population," Turchinov said on his website on Saturday. "It is a complex problem when a population deceived by (Russian) propaganda support terrorists." The separatists say they are defending themselves against a Ukrainian government they portray as 'fascist' and anti-Russian. Ukraine, backed by the United States and the European Union, accuses Russia of destabilising it, a charge that Moscow denies. Germany and France said they would support tougher sanctions against Russia, from energy to financial services, if the rebellion they see as engineered by Moscow thwarts Ukraine's May 25 presidential election, intended to stabilise the country. That would mark a further escalation of what is already the worst East-West crisis since the Cold War. -- SPA 19:47 LOCAL TIME 16:47 GMT www.spa.gov.sa/1230829