Both sides say negotiations in Berlin fell short of any new agreement while Moscow criticises what it calls a lack of clarity in Kiev's position.
Nearly nine hours of talks between Ukraine and Russia have failed to produce a breakthrough on signing a joint document, but both sides agreed to keep talking, the chief of staff to Ukraine's president said after the talks in Berlin.
Andriy Yermak, the chief of staff to President Volodymyr Zelenskyy, told a televised briefing on Thursday that both sides would likely meet again soon and hoped for a breakthrough on prisoner exchanges and the opening of checkpoints in eastern Ukraine.
"I hope that we will meet again very soon and continue these negotiations. Everyone is determined to achieve a result," he said.
Ukrainian and Russian officials met in the German capital for talks on ending the conflict in eastern Ukraine, with tensions running higher after Russia reportedly massed more than 100,000 troops near Ukraine's borders in recent weeks.
Russia said the latest round of talks with Ukraine, France and Germany on the conflict in eastern Ukraine fell short of any new agreement and criticised what it called a lack of clarity in the Ukrainian position.
Russian envoy Dmitry Kozak said after a day of talks in Berlin that Ukraine's vision of the future of the separatist-controlled Donbass region was unclear.
"We did not manage to overcome this," he said.
The conflict in the breakaway Donetsk and Luhansk regions, known together as the Donbass, simmers on despite a notional ceasefire.
Observers from the Organisation for Security and Cooperation in Europe (OSCE) record frequent violations, sometimes running into hundreds of incidents daily.
Ukraine says some 15,000 people have been killed since 2014.
Representatives of Russia, Ukraine, the OSCE and the two separatist regions signed a 13-point agreement in February 2015 in Minsk, that was also backed by the leaders of France and Germany.
Ukraine committed to accord
Russian Foreign Minister Sergey Lavrov accused Ukraine on Thursday of trying to rewrite the agreement and cherry-pick only the elements most advantageous to it.
Ukraine says it is committed to the accord.
"The Ukrainian side is set on constructive dialogue. Everyone confirmed today that we have the Minsk agreements and they need to be fulfilled," Yermak said.
Ukraine rejects Moscow's assertion that it has nothing to do with the conflict, saying Russia has forces inside Ukraine fighting alongside the separatists.
Kiev refuses to negotiate with the heads of the breakaway regions but President Volodymyr Zelenskiyy has proposed direct talks with Russian President Vladimir Putin, which the Kremlin has so far rejected.
Russia denies planning to invade Ukraine but says it wants to enforce "red lines" to make sure that its former Soviet neighbour does not join NATO and that the alliance does not set up bases and missiles there.