Ukrainian President Volodymyr Zelenskyy on Sunday accused Russian soldiers of committing war crimes and killing civilians in Kherson, parts of which were retaken by Ukraine's army last week after Russia pulled out.
"Investigators have already documented more than 400 Russian war crimes. Bodies of dead civilians and servicemen have been found," Zelenskyy said in his nightly video address, as quoted by the Reuters news agency.
"The Russian army left behind the same savagery it did in other regions of the country it entered," he said.
Mass graves have been found in a number of places across Ukraine since the start of the Russian invasion, including civilian bodies showing evidence of torture discovered in the Kharkiv region and in Bucha, near Kyiv.
Ukraine has accused Russian troops of committing the crimes, but Russia has denied its soldiers targeted civilians in Ukraine.
A United Nations commission in October said war crimes were committed in Ukraine and that Russian forces were responsible for the "vast majority" of human rights violations in the early weeks of the war, noted Reuters.
Ukrainian troops arrived in the center of southern Kherson region on Friday after Russia abandoned the only regional capital it had captured since Moscow launched its invasion in February.
While it would appear a major Russian setback, the Kremlin insisted that Kherson was still part of Russia and that it did not regret annexing the entire Kherson region at a lavish ceremony in late September.
"This is a subject of the Russian Federation. There are no changes in this and there cannot be changes," Kremlin spokesman Dmitry Peskov told reporters on Friday.
Asked by reporters whether Russia regretted annexing Kherson, Peskov said the Kremlin had "no regrets" about the move.