President Volodymyr Zelenskyy says Ukrainian authorities have found a mass burial site near a recently recaptured northeastern city previously occupied by Russian forces.

“A mass grave of people was found in Izium in the Kharkiv region. The necessary procedures have already begun there. More information – clear, verifiable information – should be available tomorrow,” Zelenskyy said in his nightly televised address.

Associated Press journalists saw the site in a forest outside Izium on Thursday. A mass grave bore a marker saying it contained the bodies of 17 Ukrainian soldiers. It was surrounded by hundreds of individual graves with only crosses to mark them.

Zelenskyy invoked the names of other Ukrainian cities where authorities said retreating Russian troops left behind mass civilian graves and evidence of alleged war crimes.

“Buch, Mariupol, now, unfortunately, Izium. … Russia leaves death everywhere. And it must be held accountable for it. The world must bring Russia to real responsibility for this war,” he said.

Russia’s forces left Izium and other parts of the Kharkiv region last week amid a stunning Ukrainian counteroffensive. On Wednesday, Zelenskyy made a rare trip outside Ukraine’s capital to watch the raising of the national flag at Izium’s city hall.

Earlier Thursday, he said that during the five months the Russians occupied the region, they “only destroyed, only deprived, only took away. They left behind devastated villages; in some of them there is not a single undamaged house. The occupiers turned schools into garbage dumps, and churches – shattered, literally turned into toilets.”

(AP)