Ukrainian President Petro Poroshenko on Tuesday has warned the European Union (EU) against "premature optimism" concerning the speedy resolution to conflict in eastern Ukraine, the presidential press service said.

During his phone conversation with European Council President Donald Tusk, Poroshenko said that the Minsk peace agreement to stabilize the situation in the east of Ukraine is not fully observed, the press service said in a statement.

Poroshenko said that despite the agreed truce there was still " no comprehensive ceasefire and complete withdrawal of heavy armament" from the frontline of fighting, the statement said.

Poroshenko's remarks came as the death toll in the confrontation between government troops and pro-independence rebels in eastern regions continues rising.

Ukrainian military spokesman Andriy Lysenko said that three government soldiers were killed and nine wounded in fighting with insurgents over the past 24 hours in the biggest daily loss of the Ukrainian army in ten days.

The warring sides in eastern Ukraine started the withdrawal of their heavy weapons from the frontline last week as a part of the latest ceasefire agreement reached on Feb. 12 in Minsk, the capital of Belarus.

The deal, aimed at ending the conflict that has killed over 6, 000 people, also includes a complete cease of hostilities, clear timelines for elections in eastern Ukraine, border control and prisoner exchange.