The death toll from Tuesday's Russian strike on the Ukrainian city of Kupyansk has risen to eight people, authorities said, after Ukrainian rescuers found another two bodies in the rubble.

Kupyansk is less than 10 kilometres (6 miles) from the frontline in Ukraine's north-eastern Kharkiv region, where Moscow has made some gains in recent months.

"Unfortunately, the bodies of two more dead civilian men were found," Kharkiv governor Oleg Synegubov said on Telegram Wednesday.

That brought the death toll in Tuesday's strike to eight people, he said: "Six men and two women, including two volunteers who were evacuating people."

Russian forces struck the city with a Grom missile, he said, posting a photo of what appeared to be a burnt-out car.

Ukraine in August called on people living near Kupyansk to evacuate as Russian forces made advances in the area.

Moscow captured swathes of the Kharkiv region early in their invasion in February 2022, but Ukrainian troops have since pushed back.