Five civilians were killed around battleground town Debaltseve, six in and around rebel centre Donetsk, and five in neighbouring Lugansk region, pro-Kiev officials and rebels said.
The most fierce fighting in recent days has been around Debaltseve, where pro-Russian separatists are fighting to encircle Ukrainian forces.
The government-run Donetsk region interior ministry said five civilians had been killed there.
Another civilian was also killed in the town of Avdiivka just to the north of rebel stronghold Donetsk and 18 more were injured around Kiev-held territory in the region, the ministry said.
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Elsewhere, in neighbouring Lugansk region shelling killed five residents of frontline villages under government control, Kiev-loyal regional officials said.
The latest casualty figures come as fears grow of an escalation of the fierce fighting in east Ukraine.
Rebel leaders yesterday called for a voluntary mobilisation to boost the number of their fighters to 100,000.
Meanwhile, officials in the US say they are seriously considering arming Kiev in a move they hope will persuade Russia to halt alleged military support to the rebels.