The fighting in eastern Ukraine has pushed the country deeper into an economic tailspin, and the strife-torn nation will need billions of dollars of new asssistance this year, economists say. Less than three months after approving a $17 billion loan package for Ukraine, the International Monetary Fund has revised its forecasts, predicting a sharper economic downturn, lower tax revenues, a spike in military expenditures and new costs to repair bridges and other infrastructure damaged by fighting.