A Russian strike on the Ukrainian city of Pavlograd on Thursday killed three people, as Kyiv's counter-strikes on Russia and Moscow-annexed Crimea killed four others, including a three-year-old.
Civilian deaths in the more than four-year war have spiked this summer, with the United Nations saying last month was the deadliest since the first year of Russia's invasion in 2022, reported AFP.
Diplomatic talks to end fighting are at a deadlock.
"Three people were killed," said Oleksandr Ganzha, the governor of Dnipropetrovsk region.
"Nineteen people were wounded... Among the casualties is a two-year-old girl," he later added, saying all the wounded were in hospital.
Pavlograd, which lies in east-central Ukraine and had a pre-war population of some 100,000 people, has come under Russian attack throughout the conflict.
In Russia, officials said a three-year-old boy was killed on the outskirts of the city of Voronezh when a Ukrainian drone hit his house and set it on fire.
Located 500 kilometers (310 miles) south of Moscow, Voronezh has frequently been targeted by Ukrainian drones, with Kyiv pushing its retaliatory strikes further into Russia.
Regional governor Alexander Gusev said the boy's parents sustained "various wounds".
Ukrainian night-time attacks on Crimea, under Russian occupation since 2014, killed two people, Kremlin-installed officials said.
One more man was killed by a Ukrainian drone in Russia's Belgorod region, according to local authorities. The Belgorod region borders Ukraine and is regularly hit.
The Kremlin has refused to back down from its maximalist demands of seizing the whole of eastern Ukraine, while US-led talks on resolving the conflict have stalled.
The UN said Wednesday that there had been a 37 percent rise in civilian casualties in the Russia-Ukraine war in the first half of this year.
