Ukrainian authorities are just beginning to sift through the wreckage of the devastated city of Lyman in eastern Ukraine as they assess the humanitarian toll, and possibility of war crimes, from a months-long Russian occupation.

Few of the buildings in the city in the Donetsk region — an area which Moscow illegally claimed as Russian territory last week following a staged “referendum” — have survived without damage, and most houses are without basic utilities.

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Walls around the town bear graffitied reminders of the four-month occupation by Russian troops, with words like “Russia,” “USSR” and “Russian World” scrawled on surfaces that are riddled by bullets.

Mark Tkachenko, communications inspector for the Kramatorsk district police of the Donetsk region, said Friday that authorities are still searching for the bodies of civilians amid the destruction, and trying to determine causes of death.

“They will look at when people died and how they died. If it was in the period when the city was occupied and they have injuries from Kalashnikov rifles, then of course, it’s a war crime,” Tkachenko told The Associated Press.

While it is still unclear how many died in the city since it was overrun by Russian forces in May, he said, Lyman today has become a “humanitarian crisis” which could still hold further grim discoveries.

“Some people died in their houses, some people died in the streets, and the bodies are now being sent to experts for examination,” he said. “For now we are looking for grave sites, and there are probably mass graves.”

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The road approaching Lyman, which Russians used as a strategic logistics and transport hub during its occupation, is littered with miles of desolation left behind from intense fighting as Ukrainian troops pressed to retake it late last week.

The forests surrounding the city were decimated by the fighting, and the burned out and twisted wreckage of dozens of vehicles lined the road which was pockmarked by craters from falling rockets.

Tetyana Ignatchenko, spokeswoman for the Donetsk regional administration, said the city’s civilian infrastructure had been “completely destroyed,” and that an effort was ongoing to clear it of the bodies of Russian soldiers abandoned during their army’s retreat.

“Police and criminologists are working, looking for Russian bodies and collecting them in the streets and forests. There are very many of them because the occupiers didn’t bring them with them,” Ignatchenko said.

As they left Lyman, Russian soldiers placed mines on the bodies of some of their fallen comrades, set to explode when Ukrainian authorities attempted to clear them, said Tkachenko of the Kramatorsk district police. Some had exploded, but caused no injuries.

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As Ukrainian authorities entered the city, they found that many civilian residents had been killed by shelling while others, mostly older people, had died during the Russian occupation because of a lack of food and medicine, Tkachenko said.

Looting of civilian homes by Russian soldiers, he said, was widespread.

Anatolii, 71, a Lyman resident who lined up in the city’s central square Friday to receive humanitarian aid, said Russian soldiers generally left people his age alone, but that he had heard rumors of prolonged detentions of civilians and that his daughter’s home had been robbed.

“I was looking after my daughter’s house when they came over and opened the house with a crowbar and stole everything that they needed and escaped,” he said. “What could I say, and to whom? Could I fight with them? No.”

The liberation of Lyman came as the latest in a series of gains by Ukrainian forces as part of successful counteroffensive operations in the Kharkiv, Donetsk and Kherson regions.

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Even as Ukraine has recovered thousands of square miles of territory in the last month, Russian President Vladimir Putin signed treaties to illegally annex the Donetsk, Luhansk, Kherson and Zaporizhzhia regions. Western leaders decried the move as illegitimate and a reckless escalation of the war, which began on Feb. 24.

As Ukrainian forces moved back into liberated cities and towns, they discovered some instances of mass graves and torture sites, such as those recently observed by AP journalists in recaptured settlements in the Kharkiv region.

In one liberated city, Izium, an AP investigation uncovered 10 separate torture sites.

Ukrainian media earlier reported the discovery of a mass grave in Lyman, but authorities on site wouldn’t confirm or deny its existence and wouldn’t elaborate further, saying only that investigations were ongoing.

But Donetsk Gov. Pavlo Kyrylenko on Friday said that two burial sites had been found in Lyman, including around 200 individual civilian graves and a mass grave with an undetermined number of bodies.

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On Friday, Tetyana, who didn’t want to give her last name, wheeled a hand cart full of squashes toward her house on the outskirts of Lyman on a street where most houses bore damage from the fighting.

Her home had been heavily damaged in a Russian attack, she said, pointing at what used to be a window in her kitchen from when a rocket came through the wall.

“I was at home and fell into the bathroom, and my daughter was in the hallway. How we weren’t killed, I don’t know,” she said. “The storage shed is destroyed, the roof was destroyed, but now we’ve repaired it. Here you see the doors are also damaged.”

Tetyana pointed to a pair of green trousers she was wearing, and several camouflage coats hanging on hooks outside her house. She’d found the Russian uniforms, she said, “laying around. All my stuff was destroyed so I have nothing to wear.”

Daria Yevheniivna, 15, said that while she had spent most of the occupation at home in hiding, she now feels a new sense of hope that her city can be salvaged.

“Everything got better,” she said. “It became very calm. I don’t hear shooting anymore, and I can sleep in the house, not in the cellar. People became more kind.”

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Anatolii, who also didn’t give his last name, complained as he spoke on the central square that some of his neighbors only watched Russian television, which he said had “messed with their heads.” He has tried to influence them, he said, but without success.

“There are some people who were waiting for the Russians, but I am Ukrainian, and we don’t like them,” he said.

“War is war. This is a real war,” he said. “Russians shout that it’s a special operation, but it’s only a special operation for them. For us, it’s a real war.”