International security and aid organisations are appealing to Ukraine and Russian-backed separatists to withdraw from front lines where fighting has dramatically escalated or risk a humanitarian disaster.
Since January 29, shelling on both sides of the front line near the government-held town of Avdiyivka has been heavier than at any time since last summer. That has refocused global attention on a simmering conflict that strained relations between Russia and the West to the worst degree since the Cold War era.
On Friday Ukrainian President Petro Poroshenko blamed Russia for the latest flare-up in hostilities.
"The full responsibility for the current sharp escalation of the situation around the Avdiyivka industrial zone ... lies with Russia and the fighters that it supports," he said in a statement on Friday.
The February 2015 Minsk peace agreement only locked the two sides in a stalemate that has been broken periodically by sharp resurgences of fighting that Kiev and the Kremlin accuse each other of instigating.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
"We have had many flare-ups before and yet somehow the sides have pulled back, reverting to an uneasy, often violent static confrontational stance," said Alexander Hug, deputy head of the OSCE ceasefire monitoring mission in Ukraine.
"Now however the stakes are even higher, there is a potential humanitarian and ecological disaster about to unfold," he said in a briefing via video link from eastern Ukraine. Monitors for the OSCE, Europe's leading security and human rights watchdog, had recorded an "unprecedented" 11,000 explosions on Tuesday.
Civilians in both government- and separatist-held territory are especially at risk because damage to utilities infrastructure has left thousands with little or no access to electricity or water amidst sub zero winter cold. Persistent fighting has hampered repair efforts.
Ukraine and Russia blame each other for the flare-up. Pro-Russian separatists said six civilians had been killed and 34 wounded on their territory since Sunday, while Ukraine has reported three civilians and 15 servicemen killed in government-held areas over the same period.
