Ukraine's opposition icon Yulia Tymoshenko is addressing crowds of protesters in Kiev, after she was earlier freed from prison.
Her release came after the country's Parliament voted to oust President Viktor Yanukovych, who has gone into hiding.
Ms Tymoshenko was jailed for seven years in 2011 for abuse of power, but now she is on her way to the capital, Kiev, to join the protesters who have changed the political landscape through months of demonstrations that have left dozens dead.
After her release the former prime minister declared: "Our homeland will from today on be able to see the sun and sky as a dictatorship has ended."
Ms Tymoshenko confirmed she will run for president and added she will "make it so that no drop of blood that was spilled will be forgotten".
She later added she is "sure" Ukraine will join the European Union "and this will change everything".
The protests started last November over Mr Yanukovych's decision to have closer ties with Russia rather than Europe.
The resolution dismissing Mr Yanukovych was passed by deputies in the assembly who applauded and sang the national anthem. Early elections have also been set for May 25.
Speaker Oleksander Turchynov said Mr Yanukovych had "abandoned his constitutional responsibilities, which threatens the functioning of the state, the territorial integrity and sovereignty of Ukraine".
Mr Yanukovych has been blocked from taking a plane to Russia, Mr Turchynov said.
"He tried to take a plane to Russia but he was blocked in doing so by border police. He is currently hiding somewhere in the Donetsk region."
Before Parliament voted, Mr Yanukovych reportedly told a local TV station in Kharkiv he would not resign or leave Ukraine, comparing the situation in the country to the Nazis coming to power in 1930s Germany.
He called the opposition "gangsters" and said he would remain in southeast Ukraine while they were "terrorising" the country. He also refused to sign any of the new laws and labelled the unrest a "coup".
Police have abandoned posts around Kiev as protesters claimed full control of Kiev the city and took up positions around the president's office and Mr Yanukovych's grandiose residential compound.
Meanwhile, Russia has criticised European Union ministers who helped broker Friday's peace deal between the two sides and protesters.
Russian Foreign Minister Sergey Lavrov told US Secretary of State John Kerry the deal has been "sharply degraded by opposition forces' inability or lack of desire" to respect it.
The country's envoy to Ukraine, Vladimir Lukin, said he could not understand "how after recognising the legitimacy of President Yanukovich, the parliament, all the state structures, my European colleagues can then come to Kiev and go to the nationalist-revolutionary and terrorist Maidan and say there - down with the government they recognised".
Authorities say some 77 people have been killed over three days of violence in Kiev this week.
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