Ukraine on Wednesday reported seven people had been killed in four regions of the war-battered country, as Russia presses gains on the front line where Kyiv's troops are struggling.

A missile attack Wednesday on the eastern Sumy region that borders Russia killed two and wounded three. regional authorities said on social media.

The governor of the frontline Donetsk region, which the Kremlin claims is part of Russia, said three people had been killed in separate attacks on Tuesday.

Governor Vadym Filashkin said two people had been killed in the town of Toretsk and another person was killed in an attack on the frontline town of Selidove on Tuesday, which is routinely struck by Russian forces.

In the southern Kherson region, which the Kremlin also claimed to have annexed in 2022 even though it is still fighting for control of the Black Sea territory, the governor said Russia had shelled housing and infrastructure facilities.

"One person died as a result of Russian aggression," said Oleksandr Prokudin, Kherson's governor.

Last weekend, Russian forces carried out one of the single deadliest attacks in weeks on the northeastern Kharkiv region which borders Russia, hitting a busy hardware store.

Prosecutors said Wednesday that the toll from the strike had risen to 19, after a 40-year-old employee of the store who sustained severe burns during the attack died in hospital.