The new government has taken a sharp turn away from Moscow, and is eager to form closer ties to the European Union.
But if Russia expected the Ukrainian military to go easily, handing over its weapons as soon as it was asked, things turned out far more complicated.
Instead, military installations across Crimea – many of them surrounded or taken over by Russian forces – have refused to surrender, raising the tension and leading to fears of all-out combat. Ukraine's new government has ordered the bases to remain loyal to Kiev.