The toll included three servicemen whose deaths were reported on Sunday, when Ukraine said it had repelled an attack by rebels in the frontline town of Avdiyivka. The separatists reported heavy shelling of their positions in the area, with one rebel fighter killed.
"Around Avdiyivka the enemy twice tried to storm our positions and, suffering losses, were forced to retreat," the Ukrainian military said in a regular update on the state of the conflict.
Close to 10,000 people have been killed since fighting between Ukrainian troops and rebels seeking independence from Kiev erupted in April 2014.
The latest clashes came ahead of a visit by President Petro Poroshenko to Berlin on Monday to discuss the state of the conflict with Chancellor Angela Merkel, who helped broker a much-violated peace deal in early 2015.
Ukraine and NATO accuse the Kremlin of supporting the rebels with troops and weapons, which it denies. The United States and European Union have imposed sanctions on Russia over the conflict, as well as for its annexation of Crimea.
Ukraine is anxious that international resolve to hold Russia to account may waver following the inauguration of U.S. President Donald Trump. Trump has expressed a desire to improve ties with Moscow and spoken of possibly lifting sanctions.
A Ukrainian soldier walks through a shell-damaged factory during a battle with pro-Russian separatists at Avdiyivka, in Ukraine's Donetsk Oblast. File picture on June 25, 2016. AFP.
Five Ukrainian soldiers were killed and nine wounded as a result of an offensive by pro-Russian separatists over the weekend, the Ukrainian military said on Monday - the deadliest fighting in eastern regions since mid-December.
