A senior Russian army lieutenant who fled Russia told ABC News he witnessed his country's troops torture prisoners in Ukraine, including beating and threats to rape them.
Konstantin Yefremov, the most senior Russian soldier to defect and speak out openly against the war, is now in hiding and spoke to ABC News from Mexico. He is currently seeking to apply for political asylum in the United States.
"I want that what I saw, what I was witness to, becomes known to society. So that the truth is uncovered," Yefremov said.
"I know that at home there only awaits me, in the best case, a lengthy prison term and, in the worst, they'll simply execute me," he said. "But to hide at home and wait for them to come for you, that's humiliating. And I can't be silent any longer. I don't want to be silent."
Yefremov, 33, spent three months as an officer in areas of Ukraine's southern Zaporizhzhia region that were occupied by Russian forces in the first phase of the war. During that time, he said he personally witnessed the torture of Ukrainian prisoners during interrogations, including the shooting of one POW in the arms and legs and threats of rape.
Yefremov has provided ABC News with documents confirming his identity as well as photos and videos that ABC has verified show him in southern Ukraine during the period he describes.
His unit, the 42nd Motorised Rifles Division -- usually based in Chechnya -- entered Ukraine from Crimea in the first days of the invasion, according to Yefremov.
Up until then, he said his commanders had told the troops they were to take part in exercises and that he, like most of his comrades, had not believed there would be war. The men only understood they really were going into Ukraine on the morning of the invasion when they heard the sound of artillery, he said.
Yefremov, who had served for nine years in the military, said he was appalled and claims that he tried to quit the military shortly after the invasion began. He said he left his unit and got in a taxi to drive him out of Crimea but, after he was threatened with imprisonment for desertion, he said he decided to return to his unit -- something he said he now regrets.
Once in Ukraine, he said he was assigned to a squad guarding an artillery position close to the Ukrainian city of Melitopol and then later his division's rear headquarters.
It was there -- the division's rear headquarters -- where he alleges he saw the brutal mistreatment of Ukrainian prisoners.
Yefremov said he was present when a drunken colonel began interrogating a young Ukrainian soldier who had admitted to being a sniper.
"They broke that prisoner's nose, they knocked out his teeth," said Yefremov. For more than a week, he said, the colonel tortured the Ukrainian POW everyday, subjecting him to a mock execution and threatening to rape him.
The colonel would "pull down his trousers and say to the other soldiers, 'Bring a mop -- now I'm going to put this mop into your rear. I'll video it and send it to your girlfriend,'" Yefremov recalled.
At one point, Yefremov said the colonel shot the prisoner in the arm and leg, breaking the bone.
"They bandaged him up, stopped the bleeding. Took him back to the garage with the other prisoners," Yefremov said.
Yefremov said he and other Russian officers secretly moved the injured Ukrainian to a Russian military hospital, dressing him up in a Russian army uniform because they feared doctors there would refuse to treat him or that wounded Russian soldiers might even kill him.
The prisoner was returned some days later wearing a cast.
"After that, the colonel, for several days, beat him again," Yefremov said.
Yefremov said three Ukrainian POWs captured were kept in a garage and made to sleep on the ground. He said the Russian troops were ordered not to feed the men anything other than crackers and water and that the prisoners were routinely beaten.
Yefremov said he and some other Russian soldiers tried to help the POWs as best they could, sneaking them food and cigarettes.
"I'm not trying to excuse myself. Or show how humane I was -- I understand I shouldn't have been there at all," he said.
ABC News is unable to independently verify Yefremov's torture allegations, but they resemble similar accounts of torture and abuse of prisoners by Russian forces widely documented in Ukraine.
Yefremov painted a picture of his own army plagued by ill-discipline and poor supplies. He said the men at the artillery unit he was guarding almost immediately ran short of food and water, reduced to hunting for hares and pheasants to feed themselves.
"We weren't supplied with anything. No tents, there wasn't enough basic food. We were occupied not so much with any military operations, as with our own survival," he said.
He said he also witnessed many incidents of Russian troops looting -- even taking things like lawnmowers, musical instruments and buckets.
Yefremov said most Russian troops had little motivation to fight and that the majority did not believe the Kremlin's justifications for the war, such as its claim to be "de-Nazifying" Ukraine.
"70% of the Russian Armed Forces don't believe in that. They understand that it's a pretext for invasion, a pretext for a crazy dictator to realize his ideas with their hands," he said.
He said many other soldiers had believed the war would end quickly and they would avoid heavy fighting but harsh new laws penalizing refusal to fight means it is now too late to resign.
"A Russian soldier … has been put in the position that either he goes fight or he sits in prison. They've said to him, 'Go and kill or we'll jail you,'" he said.
Yefremov said when he was rotated home to Chechnya in May, he decided he would not return to Ukraine. He refused an order to re-deploy and was accused of insubordination, after which he was discharged from the military in October.
But after president Vladimir Putin ordered a mobilization last fall, he said he realized his experience meant he would likely be called up. He said he went into hiding in Chechnya and then contacted a human rights group, Gulagu.net, to help him escape Russia.
Yefremov's account is supported by military documents detailing the insubordination case against him, that record him refusing to deploy to Ukraine in June.
For the past month he said he has been trying to apply for asylum in the U.S., but so far has been unable to meet with any American diplomatic staff. He said had been attempting to apply through the Customs & Border Protection's One app, a mobile phone application that the U.S. government requires asylum seekers trying to cross the border from Mexico to first submit their applications through.
Yefremov was the lead officer of a mine-clearing unit and he said previously he had worked on demining areas of Chechnya. He said he hadn't participated in Russia's 2014 seizure of Crimea and covert invasion of Donbas -- or its operation in Syria -- saying he had avoided those tours out of a personal conviction that they were wrong.
He said he fully supports Ukraine's efforts to liberate its territory and that he believes Russia now has no hope of winning the war.
He also called on his fellow soldiers to find ways to leave and "to not participate in that insanity," saying they were being exploited by the Russian leadership.
"A lie can't win," he said. "They are free people defending their land."
"I gave an oath by which I swore to protect my people. And so did all Russian military personnel. But the whole Russian army has broken that oath. They have all become Putin's private military company," he said.
Despite opposing the war, he said he could not excuse himself for taking part.
"I, in no way, am justifying myself. I'm guilty before the Ukrainian people that I came with a weapon in my hands as an uninvited guest. As long as I live I will feel that guilt," he said.