Ukraine's currency slumped to its lowest level in five years Wednesday, adding to pressure on President Viktor Yanukovych to resolve a political crisis at home so he can secure a financial aid package from either Russia or the west.

The U.S. dollar was quoted above 9.00 against the hryvnia for the first time since February 2009, according to traders, with Ukraine's national currency going from its recent steady decline into free fall. The exchange rate is widely viewed in Ukraine as a bellwether of economic stability, and...