Fighting has continued around the flashpoint town of Debaltseve in eastern Ukraine, marring a ceasefire between government forces and Russian-backed insurgents that reduced violence across the region.
The leaders of Ukraine, Russia, Germany and France called for the ceasefire to be respected along the whole frontline, four days after their 17-hour talks delivered a truce and framework plan to resolve the conflict.
The quartet said they would hold another conference call on Monday, and Ukrainian president Petro Poroshenko said the planned withdrawal of heavy artillery from the frontline would only take place once a "full and unconditional" ceasefire was in place; the pull-back is supposed to start tonight.
“Unfortunately, the peace process is today under great threat because the militants are using the tense situation around Debaltseve to break the ceasefire regime,” Mr Poroshenko said when declaring the start of the truce on Saturday night.
He said he would not reveal how Ukraine would respond if “probably the last chance for peace” in eastern regions was wrecked, but vowed in a televised address: “If we are struck on one cheek, we will not offer the other. And so help me God.”
Ukraine's foreign minister Pavlo Klimkin said that failure of "Minsk 2" – following the collapse of a previous ceasefire agreed in the Belarusian capital last September – would provoke "an extremely tough reaction from the whole civilised world. And I don't just mean sanctions."
The White House is under domestic pressure to send US weapons to Kiev, and the European Union has pledged to tighten sanctions on Moscow if it fails to rein in the separatists.
Kiev accused the rebels of continuing to attack its forces around Debaltseve and in a few other locations, while the separatists made the same claim against government troops and insisted the town was theirs.
"Of course we can open fire, it is our territory," said senior militant commander Eduard Basurin.
Ukraine’s military said rebels fired on government forces 60 times on Sunday, and were intent on seizing Debaltseve and “using all types of weapons” to provoke Kiev’s troops to respond, so they could be blamed for breaking the truce.
The separatists say thousands of Ukrainian soldiers are trapped in Debaltseve, but Kiev insists they are not surrounded and will not surrender.
Gennady Moskal, the Kiev-appointed governor of the Luhansk region that is partly held by the rebels, said Russian troops near Debaltseve had been replaced by Cossacks "who signed nothing" and rejected the truce; he claimed they were seeking to seize the road from Debaltseve to the government-held town of Artemivsk.
Moscow denies sending arms and soldiers to help the rebels, but insists on keeping open its border with militant–held areas and fails to explain the presence of vast amounts of Russian weaponry and ammunition in rebel hands.
International aid groups hope the ceasefire will allow them to increase efforts to help those affected by a conflict that has killed more than 5,400 people and displaced more than one million.
