Reuters) - Billionaire financier George Soros has urged the West to step up aid to Ukraine, outlining steps towards a $50 billion (33.22 billion pounds) financing package that he said should be viewed as a bulwark against an increasingly aggressive Russia.Writing in the New York Review of Books, Soros said Europe and the United States needed to balance sanctions imposed on Russia with large-scale assistance to near-bankrupt Ukraine, which risks defaulting on debt as a result of turmoil caused by pro-Russia separatist fighting.