Five Ukrainian servicemen have been killed and four wounded in the past 24 hours as a result of attacks by pro-Russian rebels in separatist eastern regions, Ukrainian military spokesman Oleksandr Motuzyanyk says.
This follows a report of the deaths of seven Ukrainian soldiers last Tuesday - the highest daily casualty figure for government troops since last August.
A ceasefire signed in February 2015 has failed to quell all fighting in Ukraine's separatist east, with each side accusing the other of violations.
Motuzyanyk highlighted the government-controlled frontline town of Avdiyivka, north of separatist-held Donetsk city, as a recent hot spot for rebel attacks from both light and heavy weapons, including mortars.
Russia denies Western charges it has provided the rebels in the Luhansk and Donetsk regions with arms and troops in a conflict that has killed some 9000 people and led to Western economic sanctions against Moscow.
On Saturday rebel officials said two civilians had been wounded as a result of shelling by Ukrainian troops, separatist website DAN reported.