The Ukrainian military says one serviceman was killed in fighting in the east over the past 24 hours, while separatists accused government forces of killing three civilians in the areas controlled by the pro-Russian rebels.
Ukrainian military spokesman Andriy Lysenko said at a briefing on June 23, "As a result of fighting in the past 24 hours, one of our soldiers has been killed and another 12 have been injured."
Commanders and political leaders of the self-declared Donetsk People's Republic said the strikes started on June 22 and continued through the night.
The fighting has pushed to more than 60 the number of soldiers and civilians killed this month.
Foreign ministers from Russia, Ukraine, Germany, and France are due to meet in Paris later on June 23 in the hope of calming the latest upsurge in violence that has claimed some 6,500 lives since erupting in March 2014.
The meeting comes as clashes threaten to spiral into all-out conflict after a three-month lull that followed a German- and French-brokered cease-fire deal in February in Minsk.
Based on reporting by AFP and Interfax