The Ukrainian army said on Saturday that a soldier had been killed and three others wounded in the country's pro-Russian separatist east, amid rising tensions in the conflict-torn region.
It was the fourth Ukrainian soldier killed in the past week.
The wounded soldiers were being treated in hospital and their injuries not life-threatening, the army said.
Ukrainian positions on the frontline had been targeted by artillery, mortars, grenade launchers and machine gun fire, it said on Facebook.
"Over the past two weeks, there has been an increasing number of ceasefire violations," the Organization for Security and Co-operation in Europe (OSCE), which is deploying hundreds of observers to the zone, said on Thursday.
The war, which has left more than 13,000 people dead, broke out in 2014 shortly after Russia annexed the Crimean peninsula.
Russia has always claimed that its support for the separatist regions was purely political, but Kiev and its Western allies have accused Moscow of sending troops and weapons.
After a largely respected truce in the second half of 2020, tensions have risen again this year, especially in the spring when Moscow deployed nearly 100,000 troops to Ukraine's borders for several weeks.