The ceasefire agreed last July raised hopes of ending the conflict that erupted in 2014 with the annexation of Crimea by Russia and resulted in the loss of 13,000 lives.
“We have seen an escalation of the conflict in recent weeks,” said Andriy Yermak, head of the Ukrainian presidency.
“This is a deliberate provocation against the Ukrainian armed forces to end the ceasefire,” he added during a conference held by the think tank of the Center for European Policy.
Eight Ukrainian soldiers have been killed since mid-February. Kiev blamed the clashes in Moscow and the separatist leaders and accused them of using military equipment banned under the second Minsk agreement signed in February 2015 to resolve the conflict.
Yermak urged Western countries, including France, Germany and the United States, to “step up their efforts” to resolve the conflict.
According to Moscow, Kiev and its Western allies accuse Russia of sending troops and weapons to support the separatists.
The Kremlin said earlier this week that it was “deeply concerned” about the escalation of tensions and blamed Ukrainian forces for the escalation of the conflict.
“We are recording more and more bombings from the Ukrainian side,” said Kremlin spokesman Dmitry Peshkov, urging Kiev to abide by the agreements to end the war.
European Council President Charles Michel said during a visit to Ukraine this week that the EU has no plans to lift economic sanctions against Russia over its role in the conflict.
He also said that Russia had not reciprocated the “positive steps taken by Ukraine” to end the war and described Moscow as “a party to this conflict and not a mediator”.