After Russian troops retreated, Ukrainian President Volodymyr Zelenskyy said that there were torture chambers and mass graves in the country's Kharkiv region.

Ukrainian Ambassador to the United States Oksana Markarova said during a Sunday interview with ABC News that war crimes of massive proportions are occurring as a result of the Russian invasion that began in February.

In a video address late Saturday, Zelenskyy said that more than 10 torture chambers had been found in the liberated areas of the region. They dropped the torture devices as they fled.

An interior view shows a basement of a building, which Ukrainian authorities say was a makeshift Russian prison and torture chamber during Russia's invasion in the village of Kozacha Lopan, in Kharkiv region, Ukraine September 18, 2022. REUTERS/Viktoriia Yakymenko
An interior view shows a basement of a building, which Ukrainian authorities say was a makeshift Russian prison and torture chamber during Russia's invasion in the village of Kozacha Lopan, in Kharkiv region, Ukraine September 18, 2022.
REUTERS/Viktoriia Yakymenko

Zelenskyy said that there were rooms at the railway station that were designed to be used for torture.

The settlement just over a mile from the Russian border was taken over by the Ukrainians.

Zelenskyy said there was clear evidence of torture and humiliation. There is evidence that Russian soldiers shot at the buried just for fun.

An interior view shows a basement of a building, which Ukrainian authorities say was a makeshift Russian prison and torture chamber during Russia's invasion in the village of Kozacha Lopan, in Kharkiv region, Ukraine September 18, 2022. REUTERS/Viktoriia Yakymenko
An interior view shows a basement of a building, which Ukrainian authorities say was a makeshift Russian prison and torture chamber during Russia's invasion in the village of Kozacha Lopan, in Kharkiv region, Ukraine September 18, 2022.
REUTERS/Viktoriia Yakymenko

The bodies of 450 people, mostly civilians, were found in a mass grave in the city of Izium.

Some of the bodies were found with rope around their neck, according to a report.

The bodies of 116 people were recovered after the city was liberated from the Russians.