Ukrainian President Volodymyr Zelenskiy has said in a video address that authorities found a mass grave in the recaptured city of Izium, adding that more information should be available.
A regional police official confirmed that more than 440 bodies had been found, adding some of the people had been killed by shelling and air strikes.
Zelenskiy put the blame on Russia and likened the discovery to what happened in Bucha, on the outskirts of the capital Kyiv, in the early stages of the late February invasion by Russian forces.