DONETSK, Ukraine -- Ninety percent of voters in a key industrial region in eastern Ukraine came out in favor of sovereignty Sunday, pro-Russian insurgents said in announcing preliminary results of a twin referendum that is certain to deepen the turmoil in the country. Roman Lyagin, election chief of the self-styled Donetsk People's Republic, said around 75 percent of the Donetsk region's 3 million or so eligible voters cast ballots, and the vast majority backed self-rule.