Thirteen government soldiers and at least as many civilians have been killed in the past 24 hours in eastern Ukraine's separatist conflict after the collapse of peace talks, Kiev authorities said. Hopes of easing the situation evaporated on Saturday with Ukraine's representative and separatist envoys accusing the other of sabotaging negotiations.
"Fighting continues across all sections of the frontline," Kiev military spokesman Volodymyr Polyovy said in a briefing.
The Organisation for Security and Co-operation in Europe, which took part in the talks in Minsk, Belarus, along with envoys from Ukraine and Russia, said rebel delegates had not been ready to discuss key points of a peace plan.
"In fact, they were not even prepared to discuss implementation of a cease-fire and withdrawal of heavy weapons," the OSCE said in a statement.
It said rebels had instead pushed for a revision of a cease-fire plan agreed in Minsk last September.
The terms of that 12-point protocol have been repeatedly violated but Kiev and foreign governments see it as the only viable roadmap to end the nine-month-long conflict in which more than 5,000 people have been killed.
In eastern Ukraine, the Kiev military reported no let-up in rebel attacks on government positions.
Clashes are intense around the town of Debaltseve, Polyyovy said, referring to a Kiev-held transport hub connecting the two main rebel strongholds that separatists aim to cut off.
"There is no question of encirclement or cutting off of the main communication lines. The situation is under control," he said.
The rebel advance has succeeded in seizing part of nearby Vuhlehirsk from Kiev troops, Polyovy said. On Sunday the town was being pounded by near-constant shelling, a Reuters witness reported.
The Interior Ministry said on Sunday seven civilians had been killed in shelling on Sunday of Debaltseve, while the Luhansk regional administration said three civilians had been killed in shelling across the region overnight.
Residents are being encouraged to abandon the areas of fiercest fighting, where many have been living in makeshift bomb shelters, waiting for breaks in the bombardment to make quick trips for food and water.
In Kiev-controlled Slaviansk, refugees arrived in buses from Debaltseve and other frontline towns.