Ukraine’s president has visited the country’s eastern frontline amid an escalation of tensions with neighbouring Russia that has raised fears of a resumption of large-scale hostilities.
In Moscow, a senior Kremlin official sternly warned Ukraine against using force to reclaim control of the rebel east, saying that this might force Russia to step in to protect civilians there.
The conflict with Russia-backed separatists in eastern Ukraine erupted shortly after Moscow’s 2014 annexation of Ukraine’s Crimea peninsula. More than 14,000 people have died in the fighting.
Analysis: Russia using old Putin tactic to justify military presence near the Ukrainian border
Officials in Ukraine and the West have raised concerns about increasingly frequent ceasefire violations in the country’s industrial heartland, known as Donbas.
They also accused Russia of sending troops and weapons along the border to support the rebels there – accusations the Kremlin has denied.
And after tweeting that he wanted to “be with our soldiers in the tough times in Donbas,” the Ukrainian president, Volodymyr Zelenskiy, arrived in the heart of the conflict area on Thursday.
He said a 23-year-old Ukrainian soldier had been killed in the area on Wednesday night.
He told troops: “Thank you for keeping people calm and defending our land. You are a true example of heroism and dedication. We remember every warrior who died defending our state.”
Mr Zelenskiy has accused Russia of flexing its military muscle and held a series of calls with Western leaders to rally support for Ukraine amid the tensions.
Russia has rejected the claims, arguing it can deploy its troops wherever it deems necessary on its territory, and that they are not threatening anyone.
It has accused Ukrainian authorities of trying to stoke up tensions in the east for domestic policy purposes.
The White House is said to be “increasingly concerned by recent escalating Russian aggressions in eastern Ukraine”, including Russian troop movements on Ukraine’s border.
Press secretary Jen Psaki said: “Russia now has more troops on the border with Ukraine than at any time since 2014.
“Five Ukrainian soldiers have been killed this week alone. These are all deeply concerning signs.”
Speaking at a panel discussion with political experts in Moscow, Dmitry Kozak, a Putin aide who serves as Russia’s top negotiator with Kyiv, warned Ukraine against using military force to retake control of the eastern regions, where many residents have received Russian citizenship.
“The start of hostilities will the beginning of an end for Ukraine,” he said. “It would mean shooting itself not just in the foot, but in the head.”