Leaders of mainly Russian-speaking regions of eastern Ukraine that are loyal to President Viktor Yanukovich challenged the legitimacy of the national parliament on Saturday and said they were taking sole control of their territories.
The parliament in Kiev has passed a series of moves in the past 24 hours that will reduce the president's powers and pave the way to the formation of a national unity government and early presidential elections.
Mikhaylo Dobkin, Governor of Kharkov region in northeast Ukraine, told regional leaders meeting in the city of Kharkov: "We're not preparing to break up the country. We want to preserve it."
But a resolution adopted at the meeting said: "The decisions taken by the Ukrainian parliament in such circumstances cause doubts about their ... legitimacy and legality."
It added: "The central state organs are paralysed. Until the constitutional order and lawfulness are restored ... we have decided to take responsibility for safeguarding the constitutional order, legality, citizens' rights and their security on our territories."