The United Nations has announced plans to investigate reports that mass graves have been discovered in the Kharkiv region in areas occupied by Russia until Ukraine’s recent counteroffensive. Liz Throssell, a spokesperson of the U.N. Office of the High Commissioner for Human Rights, spoke on Friday.

Liz Throssell: “We have seen the reports about possible mass graves, or what we call collective graves. We’re aware of reports to which more than 400 bodies were found in a collective grave in Izium. Our colleagues in Ukraine, in the human rights monitoring mission in Ukraine, are following up on these allegations, and they are aiming at organizing a monitoring visit to Izium to determine the circumstances of the death of these individuals.”

During Ukraine’s recent counteroffensive, it recaptured about 3,400 square miles of land — that’s more land than Russia had captured over the past five months.

In other news on the war in Ukraine, Ukraine’s state nuclear agency says a Russian military strike has hit the South Ukraine Nuclear Power Plant. No damage was reported to the plant’s reactors. The facility is Ukraine’s second-largest nuclear power plant. Meanwhile, the 35-nation board of the International Atomic Energy Agency has approved a resolution demanding that Russia end its occupation of Zaporizhzhia, the largest nuclear power plant in Europe.