The civilian deaths came in Gorlivka, some 30 kilometres north of the rebel stronghold of Donetsk, late Friday, the local council in the rebel-held city said.
It added that a further 12 people were also injured when artillery struck a residential area of the city, seriously damaging two apartment blocks and destroying six flats. The council did not specify who fired the mortars, AFP reported.
Earlier Saturday, security officials in Kiev said that three more Ukrainian soldiers had been killed in fighting in the east over the past 24 hours, taking to seven the total number of servicemen killed across the region in the past day.