Ukraine's acting president has warned Russia that troop movements outside its naval base in Crimea would be seen as an "act of aggression". Armed men seized regional government headquarters and parliament and the Russian flag is flying from buildings
Ukraine has suffered its bloodiest day in 22 years, with at least 39 people killed during today's violent clashes in Kiev.
Riot police were captured on video shooting from a rooftop at protesters in the capital, while demonstrators hurled petrol bombs and paving stones to drive the security forces away.
Kiev's city health department said 67 people had been killed since the clashes started on Tuesday, which meant at least 39 died today.
That means today is by far the worst violence seen in Ukraine since the country emerged from the crumbling Soviet Union 22-years-ago.
Ukraine's interim President has expressed concerns about signs of separatism as opposition in Russian-speaking regions grows.
Hundreds of Ukrainians and journalists flocked to the presidential palace, as reports emerged that President Yanukovich had left the city.
Vitali Klitschko was met with boos from anti-government protesters, as he attempted to convince them a peace deal is best course of action.