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
Ukrainian president Viktor Yanukovich has blamed opposition leaders for the latest wave of violence to hit the country, urging them to distance themselves from the "radicals".
The violent protests, which began in November after the government walked away from a trade pact with the EU before forming stronger ties with Russia, escalated yesterday after police attempted to move protesters out of Independence Square.
"They crossed the limits when they called people to arms. And it is a blatant violation of the law. I have some advisors who try to persuade me to the use of force. But I always thought the use of force as a wrong approach," Mr Yanukovych said.
He continued: “Therefore, I once again urge the leaders of the opposition, who argue that they too seek a peaceful settlement immediately disassociate themselves."
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.