People hold tied Polish, right, and Ukrainian flags during a demonstration supporting the opposition movement in Ukraine, in Warsaw, Poland, Sunday, Feb. 23, 2014. A top Ukrainian opposition figure assumed presidential powers Sunday, plunging Ukraine into new uncertainty after a deadly political standoff - and boosting long-jailed Yulia Tymoshenko's chances at a return to power. The whereabouts and legitimacy of President Viktor Yanukovych are unclear after he left the capital for his support base in eastern Ukraine. (AP Photo/Czarek Sokolowski)