Three more Ukrainian soldiers have been killed during fighting in the east over the past 24 hours, security officials in Kiev said Saturday.
The announcement brings to seven the total number of troops killed across the region in the past day. Another 10 troops have been injured, according to the officials.
An AFP reporter in the rebel stronghold of Donetsk reported low-level bombardments around the airport early Saturday although a local official later said this had increased in intensity.
The casualties come with the unrest in Ukraine high on the agenda at a G20 summit in Brisbane, where Western leaders are expected to put fresh pressure on Russian President Vladimir Putin.
Russia denies involvement in the conflict but Western powers fear a possible escalation, with NATO this week accusing Moscow of sending fresh armoured columns and troops across the border to bolster pro-Russian separatist forces.
Seven months of fighting in eastern Ukraine has claimed the lives of more than 4,000 people, according to figures from the United Nations.
A ceasefire agreed in September has stopped fighting along much of the frontline but not artillery bombardments around strategic hotspots.