Ukrainian President Volodymyr Zelensky has accused Russia of turning the eastern Donbas region into "hell" as intense fighting erupts there.

Speaking during his overnight address from Kyiv, he said Russian forces had razed the region. "There are constant attacks on the region around Odessa, on the cities in central Ukraine. "Donbass has been completely destroyed," he said.

"All this does not and cannot have a military explanation for Russia," Zelensky added.

"This is a deliberate and criminal attempt to kill as many Ukrainians as possible. "Destroy as many houses, social facilities and enterprises as possible," said the Ukrainian leader.

On Thursday, the Ukrainian Defense Ministry accused Russia of intensifying attacks in Donbas and preventing civilians from fleeing.