Clashes in the economically-vital border regions of Lugansk and Donetsk have picked up with renewed vigour since Ukrainian President Petro Poroshenko tore up a 10-day ceasefire earlier this week.
His decision on Monday was immediately followed by the launch of a "massive" offensive by Kiev that led President Vladimir Putin to warn that Russia has the right to protect its compatriots in Ukraine.
The head of Ukraine's national security and defence council said government forces had regained control over 23 of the conflict zone's 36 local regions. But the military also reported the loss of nine soldiers in the latest overnight exchanges of mortar fire.
But the ongoing low-scale warfare on the European Union's eastern frontier has also unified the West in its biggest pushback to date against Putin's seeming attempt to reassert command over former Soviet lands.
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Russia now faces the threat of devastating economic sanctions should Putin fail to explicitly order the militias to lay down their arms.
France and Germany -- still hoping to avoid new punitive steps that would damage their own economies -- have spearheaded efforts to set up new European-mediated discussions that would bring Poroshenko's envoys into rare contact with the rebel command.
Poroshenko's decision to propose the next discussions for tomorrow followed yet another telephone exchange with German Chancellor Angela Merkel and French President Francois Hollande.
The Ukrainian leader then told EU foreign policy chief Catherine Ashton that he had "proposed a place and time for the meeting and is waiting the other party's confirmation."
Kiev has balked at the idea of holding another round-table in rebel-held Donetsk -- a location in which Moscow carries widespread influence.