In Slovyansk there has been a night of heavy fighting in which government forces reclaimed a television tower and rebels retreated deeper into the city, according to the Russian Interfax agency.
Witnesses say heavy gunfire could be heard closer to the centre of Slovyansk than in recent days. There have been fatalities among the Ukrainian troops.
Arsen Avakov the interim interior minister and the man leading what Kyiv calls the “anti-terror” operation said four soldiers were killed and 30 wounded.
Media sources captured two rebel armoured personnel carriers in retreat the troops abandoning the barricade.
Warnings have come from the international community. The Russian foreign ministry said in a statement in Monday failure to halt the growing unrest would threaten peace across Europe.
And Germany believes a referendum planned by pro-Russian separatists in Donetsk next week would violate Ukraine’s constitution and make the situation even worse.