KOZACHA LOPAN, Ukraine (AFP) - Ukraine's latest suspected mass burial site is in a shell-damaged and abandoned industrial chicken farm, on a hill near the Russian border strewn with the debris of battle.

It is not known how many bodies lie there - troops and officials speak of 90 to 100 without saying how they know - but the signs of recent violence lie in rubble all around.

Parts of the turret of a destroyed tank have been tossed in the air and crashed through the shrapnel-shredded roof of a hangar-like shed, crushing empty poultry cages below.

A cold wind blows through the dust from shattered cement bricks and the handful of Ukrainian troops on guard wince occasionally when one of their own tanks lobs a shell towards Russia.

De-mining teams have not yet arrived at the site outside Kozacha Lopan, around two kilometres from the border, and the potential mass grave has yet to be disturbed.

"I was told by the soldiers who came to our village that they saw a burial place of soldiers, but they didn't specify the number," said Lyudmyla Vakulenko, head of the Kozacha Lopan local administration.

"They said a specialised unit would look into it," she added.

The forensic teams are expected later this week, once the area is deemed safe for work. On Monday, soldiers moved gingerly, avoiding unpaved areas, wary of mines and unexploded shells.

Unexploded shells

But reports of the potential mass burial will confirm the worst fears of Ukrainians, still shocked by the discovery of a makeshift forest cemetery further south in recaptured Izyum.

There, Ukrainian investigation teams found what they said were 447 bodies buried during the Russian occupation of the area: 425 civilians, including five children, and 22 Ukrainian servicemen.

The Kharkiv regional governor, Oleg Synegubov, said that most of the Izyum bodies showed signs of a violent death and that 30 of the victims appeared to have been tortured beforehand.

On Sunday, President Volodymyr Zelensky told CBS News that Ukraine had found "two more mass graves, big graves with hundreds of people", but it was not clear if he was referring to Kozacha Lopan.

It is not yet known whose bodies lie in the chicken plant. Soldiers guarding the complex told AFP they expected to find the corpses of both Russian and Ukrainian troops and local civilians.

But Vakulenko says the officer who told her of the find said the military thinks it is a grave for soldiers, and that she has received another clue as to the soldiers' potential identity.

On April 22, she says, a Ukrainian force from the 72nd Mechanised Brigade counterattacked Russian forces dug in near the chicken plant, but were beaten back with heavy casualties.

The area was finally liberated by Ukrainian forces this month, and over the weekend Vakulenko - who runs the civil administration in the border area north of the city of Kharkiv - got a call.

"Yes, there was a phone call on the community hotline from a woman named Olena. I don't know if she's a relative or a friend, just 'Olena'," Vakulenko told AFP.

"She left her phone number said that some of her relatives or friends were killed on April 22 near the village of Kozacha Lopan.

"She asked, 'Can I get some official information?' And we answered: 'So far, no. Until the exhumation is carried out. Until this unit does its work and tells us what happened'."

Under-floor bunker

Whoever is buried under the chicken plant, it seems clear who was there when the burials took place. The hangars and outhouses are full of the signs of Russian occupation.

Deep trenches have been dug under the floors of some of the sheds, each the size of the tank that would have squatted there under the cover of the cavernous, metal-roofed poultry barns.

A Russian tank crewman's leather helmet hung on a fence post, and a Russian-issue military jacket lay in the mud.

Ukrainian forces said the unit based there was recruited from Abkhazia, a breakaway region of Georgia under Russian occupation.

In the farm's mechanical workshop, a bunker has been dug under the concrete floor, and the former residents have built a makeshift gym with a concrete barbell and a punching bag made of car tyres.

A shell hole has ripped through one corner of the roof, allowing a shaft of sunlight into the gloom. AFP