In a month spent at the front line, Aleksandr, an ex-convict serving in the Russian Army, hadn’t seen a single Ukrainian soldier and had barely fired a shot. The threat of death came from a distance, and seemingly from everywhere.

Sent to guard against a potential river crossing in southern Ukraine, his hastily formed unit, made up almost entirely of inmates, endured weeks of relentless bombardment, sniper attacks and ambushes. The marshy, flat terrain offered no cover beyond the burned-out hulks of cottages. He said he had watched dogs gnaw at the uncollected corpses of his dead comrades, drunk rain water and scavenged garbage dumps for food.

Aleksandr claims that out of the 120 men in his unit, only about 40 remain alive. These survivors are being heavily pressured by the Russian military to remain on the battlefield at the end of their six-month contracts, according to Aleksandr and accounts provided to The New York Times from two other Russian inmates fighting on the front line.

“We are being sent to a slaughter,” Aleksandr said in a series of audio messages from the Kherson region, referring to his commanders. “We are not human to them, because we are criminals.”

His account provides a rare window into the fighting in Ukraine from a Russian inmate’s perspective. Units made up of convicts have become one of the cornerstones of Russian military strategy as the prolonged fighting has decimated the country’s regular forces. Aleksandr’s descriptions could not be independently confirmed, but they aligned with accounts from Ukrainian soldiers and Russian prisoners of war who said that Moscow used inmates essentially as cannon fodder.

The soldiers’s accounts were obtained through voice messages over the last two weeks, some in direct interviews and some through messages provided by family members and friends. Their last names, personal details and military units have been withheld to protect them against retribution.

Aleksandr’s testimony conveys the brutality imposed on Russian convicts, and the human cost Moscow is prepared to maintain control of the occupied territory.

The Russian Defense Ministry began to sign up thousands of inmates from the country’s jails in special units called “Storm Z” in February, after taking over a prison recruitment model used by the Wagner private military company in the first year of the war.

Aleksandr said he had enlisted in March, shortly after receiving a long prison term for homicide in central Russia. He left at home a wife, a daughter and a newborn son, and was worried that he would not survive the torture and extortions in his jail.

Like other inmate fighters, he was promised a monthly salary of $2,000 at today’s exchange rate, and freedom at the end of his six month contract, a copy of which he shared with The Times.

Wagner claims that 49,000 inmates fought for its force in Ukraine, and that 20 percent of them died. Former fighters have described brutal disciplinary measures imposed by the paramilitary group. .

However, Wagner survivors have also broadly said that they were able to collect wages and return home after six months as free men. To lift the recruitment numbers, Wagner also worked to rehabilitate the inmates in the eyes of Russian society, presenting their military service as a patriotic redemption.

Yet by February, Wagner had lost access to prisons during a power struggle with the military high command, allowing the Defense Ministry to supplant them in terms of recruiting convicts.

The size and casualty rates in the Russian army’s own inmate units are unknown. However, a tally of the country’s war deaths collected by the BBC and Mediazona, an independent news outlet, shows that inmates became the most frequent Russian casualties starting this spring, underlining the oversize contribution they have made to the country’s war effort.

The testimony of Aleksandr and three other former inmates shows how convict units have evolved under the direct control of the Russian Army. The Times obtained Aleksandr’s contact information through a Russian rights activist, Yana Gelmel, and verified his and other inmates’ identities using publicly available court records and interviews with their relatives and friends.

They have described irregular wage payments that fell far short of the amounts promised to them by the state and an inability to collect compensation for injuries. Aleksandr also said that his officers had explicitly prevented men in his unit from collecting dead comrades from the battlefield.

He claimed that this was done to prevent their families from claiming compensation, because the dead soldiers would be registered as missing rather than as killed in action.

“There were bodies everywhere,” Aleksandr said, describing the fighting on the banks of the Dnipro River in May. “No one was interested in collecting them.”

Russia’s Ministry of Defense did not respond to a request for comment.

Aleksandr also claimed that his officers used threats and intimidation to force surviving inmates to remain at the front for another year after the end of their contracts. Another inmate soldier currently serving on the Zaporizhzhia front further east said that his contract had obliged him to remain in Ukraine for an additional year after obtaining his pardon, this time as a professional soldier.

All inmates spoke of colossal casualties in their units and of their commanders’s seeming disregard for their lives.

“Every day, we live like on top of a powder barrel,” Aleksandr said. “They tell us, ‘You are nobodies, and your name is nothing.’”

After a month of training near the occupied city of Luhansk, Aleksandr said he was sent with his unit to hold a line of former holiday homes near the Antonovskiy Bridge, an area that Ukraine has been targeting with hit-and-run attacks since Russia’s forces withdrew to the east bank of the Dnipro in November.

They spent the next three and a half weeks under constant bombardment from the invisible enemy, who shelled their exposed positions from across the river and targeted them with snipers and in night ambushes. Enemy drones constantly hovered in the air.

The aim of their mission was unclear to them; they were told to simply remain in their positions. They had no heavy weapons and no means to defend themselves against Ukrainian attacks.

“I’m running around with an automatic gun like an idiot. I haven’t made a single shot, I haven’t seen a single enemy,” a former inmate from Aleksandr’s unit named Dmitri, who is now deceased, said in a voice message at the time. “We are just a bait to expose their artillery positions.” The message was shared with The Times by Dmitri’s wife.

“Why the hell do I need to be here? To sit around and shake like a rabbit because shells keep on exploding all around you?” Dmitri said in one of the messages.

Aleksandr said his unit had been left without food and water for days after asking their commanders to be relieved, forcing them to scavenge for ration biscuits and drink rain water treated with chlorine.

In late May, Aleksandr was sent on a mission to mine a riverbank. His unit was hit by a Ukrainian howitzer shell, which detonated nearby mines.

All of the other men in his detachment died instantly, he said; Aleksandr was injured.

“It was raining, and I fell into a puddle,” he said, describing the attack. “I crawled away bit by bit and then covered myself with some rubble, because I knew they would finish me off.” He said he had managed to send text messages to his unit before losing consciousness.

The next day, he was dragged out by his comrades and evacuated to a hospital in Crimea. Though he still couldn’t walk well, he was sent back to the front line, before being put in a hut in the rear with other convalescing fighters.

“It’s so scary to remain here,” Aleksandr said. “This is not our war. There’s nothing human here.”

Oleg Matsnev and Alina Lobzina contributed reporting.