Since the liberation of the area surrounding the eastern Ukrainian city of Kharkiv from Russian occupation, police say they have discovered 25 torture camps there.
In the camps, Russian troops had detained and tortured civilians under inhumane conditions, among other things, regional police chief Volodymyr Timoshko wrote on Facebook on Monday.
Some of the prisoners had been subjected to electric shocks and others had had their fingers broken, he said.
The area around Kharkiv was occupied by Russian troops for months. They only withdrew at the beginning of September after a Ukrainian counteroffensive.
Since then, 920 bodies of civilians, among them 25 children, have been discovered in the liberated region, Timoshko added. They were killed by Russian soldiers, he said.
According to investigations by Ukrainian authorities, Russian forces have also committed war crimes in other occupied territories.
After the withdrawal of Russian units from the Kiev suburb of Bucha, the bodies of more than 400 people were discovered there. Most of them had died violent deaths. The investigation is ongoing.
