KIEV, Ukraine — The crisis over Ukraine's disputed presidential election intensified Sunday, as a key eastern province called a referendum on autonomy andthe opposition demanded the current president fire his prime minister, the official winner of last week's votethat has bitterly divided this former Soviet republic. The opposition warned President Leonid Kuchma it would block his movementsunless he fired PrimeMinister ViktorYanukovych and fulfilled other demands within 24 hours. Earlier, Kuchma called on the opposition to end its four-day blockade of government buildings, saying compromise was the only solution to the crisis that has developed into a tense political tug-of-war between...