Oleg Synegubov wrote on Telegram that the dead included 24 children.

"This is an innocent civilian population, we will not forgive them for any life!" he wrote.

Synegubov said Russian forces had carried out 34 rocket and artillery strikes across Kharkiv, leaving one person dead and eight wounded.

Kharkiv, Ukraine's second city with a pre-war population of some 1.5 million, is located some 40 kilometres (25 miles) from the Russian border.

It has been a key target for Moscow's invading forces, which have battered it with bombardments but failed to capture the city.