Rival groups of pro-Russia and pro-Ukraine demonstrators have clashed in front of the regional assembly building in the eastern Ukrainian city of Kharkiv.
Meanwhile, in deposed president Viktor Yanukovych’s home town of Donetsk, an unidentified man read out “the act of the proclamation of an independent state, Donetsk People’s Republic”, in front of a white, blue and red Russian flag.
Separatists seized three public buildings in the largely Russian-speaking east demanding that referendums be held on whether to join Russia.
Around half of the region’s residents are ethnic Russians, many of whom purportedly believe Ukraine’s acting authorities are nationalists who will oppress Russians.
Kyiv condemned the seizure of public buildings.
“Dear citizens of Ukraine, yesterday the second wave of the Russian Federation’s special operation against Ukraine started,” said acting Ukrainian President Oleksander Turchynov.
“Enemies of Ukraine are trying to repeat the Crimean scenario but we will not let them do it. Last night the anti-crisis headquarters were set up and an anti-terrorist operation will take place against those who took up weapons.”
Police have reportedly cleared the protesters from the assembly building in Kharkiv, but in the city of Luhansk demonstrators had seized weapons.
Elsewhere in Donetsk, police have reportedly prevented unidentified armed gunmen from capturing a regional television centre.