A Ukrainian military spokesman says seven servicemen have been killed and 13 wounded in fighting with pro-Russian separatists in the past 24 hours.
The casualties were the highest daily losses for the Ukrainian army since mid-July, as violence continues to test a six-month-old cease-fire deal.
The fresh casualty figures come after U.S. President Barack Obama and German Chancellor Angela Merkel spoke about the recent upsurge in violence in eastern Ukraine despite the cease-fire agreement reached in Minsk back in February.
In the call to Merkel on August 26, Obama noted that Kyiv was implementing its obligations under the Minsk agreements, and reiterated that Russia must do the same, according to a White House statement.
The statement said the recent violence had resulted from increased attacks by combined Russian-separatist forces across a line of contact established under the Minsk agreements.
Earlier on August 26, representatives from Ukraine and the rebels agreed to strive for an end to all truce violations from September 1.