Ukrainian forces and Russian-backed rebels clashed heavily for a third straight day in Rebel-held city of Donetsk in Ukraine’s east.
Thousands of locals remained without power after a deadly surge in fighting.
Dozens of miners remained trapped underground after shelling caused power-cut.
The industrial hub of avdiivka came under attack from insurgents seeking to wrest back territory controlled by kiev during the nearly three-year war.
The clashes have claimed the lives of at least 13 civilians and fighters on both sides.
Ukrainian President Petro Poroshenko underscored the urgency of the situation by cutting short a visit to Berlin.
Ukraine is struggling through freezing conditions in which temperatures drop to -15 degrees celsius and homes in avdiivka are in dire need of heating.