The toll was one of the highest reported since the signing of the September 5 truce agreement, and brings the number of civilians killed in sporadic mortar and rocket attacks to 14 since the weekend.
Insurgency leaders signed up to the peace pact but soon accused Kiev of breaking the ceasefire. Some have since vowed to keep fighting until all Ukrainian forces pull out of their self-proclaimed states.
The heaviest daily clashes are being waged around the northern outskirts of the main rebel-held city of Donetsk, where outnumbered government forces have been holding on to a besieged airport since the end of May.
The military has also accused pro-Russian forces of attacking its positions near Mariupol, the government-held industrial port on the Sea of Azov that was the target of a surprise rebel counter-offensive one month ago.
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Visiting US Assistant Secretary of State Victoria Nuland, meanwhile, was putting pressure on the government to pass key anti-corruption legislation to secure emergency financial aid.
The US diplomat began a three-day visit with talks with the Ukrainian leadership yesterday and was due to meet with border guards tomorrow after the United States provided them with $3 million worth of equipment to bolster the frontier with Russia.
"Without full border control by Ukraine, it is impossible to reach peaceful regulation" of the crisis, Poroshenko said.
More 3,300 people have been killed in nearly six months of warfare.
Poroshenko later lamented the "lack of sustainable progress" of the ceasefire while speaking to German Chancellor Angela Merkel.
"Russia should use its influence on the separatists in a more pronounced manner to contribute to stabilisation," Merkel's spokesman Steffen Seibert said after the phone call.