From the frontlines, a warning to Chinese nationals considering fighting for Russia: Don't come here.

A Chinese soldier serving in the Russian Army claims that his superiors kept him for 21 days in a pit with steel bars and little room for him to stand in. His offense, he said, was a dispute with his commander over lifesaving protective gear.

Michael, not his real name, said he joined Russia’s fight against Ukraine to have a taste for military life abroad but after a brutal year on the frontlines is now convinced enlisting in Vladimir Putin’s army was a mistake.

His experience in the pit, where the 29-year-old said he could barely lift his head, killed his desire to fight for Moscow and he wants to send a message home to other Chinese nationals contemplating joining Russia’s fight. I have to speak out some truths and warn those irrational Chinese – don’t come over here, he said.

Speaking to CNN by phone, Michael said he was currently recovering from injuries sustained on the battlefield.

The world’s number two military is a sheer joke, Michael said, listing subpar equipment, inadequate logistics, mistreatment and “severe corruption” as issues within the military, complaints that have been widely documented since the war began.

Both Ukraine and Russia have used foreign fighters to bolster their forces. But the issue of Chinese mercenaries fighting for Russia was thrust into the global spotlight when Ukraine’s President Volodymyr Zelensky revealed two Chinese fighters had been captured by Ukraine in early April and claimed there were “many more” in Russia’s ranks. Zelensky demanded answers from Beijing which, in turn, denied any involvement and repeated previous calls for Chinese citizens to “refrain from participating in military actions of any party.”

Russia’s deputy foreign minister called the claims Chinese citizens were fighting in Ukraine a “complete untruth,” according to TASS, a Russian state media agency. Days later Ukraine paraded the Chinese fighters it captured in front of the media.

155 additional Chinese nationals were reportedly fighting for Russia, according to Kyiv. But the true number is likely higher, according to Zelensky. Michael and another Chinese fighter who fought alongside Russia informed CNN that they are aware of hundreds more. There have also been a few Chinese fighting on the Ukrainian side. The Ukrainian Land Forces were unable to provide a total number because each unit recruits directly, but CNN has confirmed their presence with one battalion.

After being initially turned down by the Russian army because he didn’t speak Russian, he said he joined the infamous mercenary group Wagner and was sent to fight in the Donbas region. He claims that he signed a one-year contract with Russia's Defense Ministry in May 2024, six months later, which sent him to Bakhmut. Other foreign fighters have signed similar contracts.

Michael told CNN that his contract offered 200,000 rubles ($2,400) per month and in a previous social media video said there were also bonuses when they captured territory from Ukraine – an extra 50,000 rubles ($598) for every kilometer they pushed eastward.

According to Michael, most of his Chinese comrades-in-arms are in it for the cash. As one self-proclaimed Chinese mercenary put it in a comment on Douyin: “no money, no honor.” CNN tracked the IP address of the post to a location in Russia.

Michael provided an explanation for why the money was important, describing himself and a number of Chinese fighters fighting on Russia's frontline as being "from the bottom of the heap" in his homeland's highly competitive society and slowing economy. Another Chinese national who said he fought for Russia and documented his exploits online told CNN what he earned as a mercenary was about three times what he was previously earning at home.

The man, 37, who CNN has chosen not to name, said he spent a year in Russia’s army from July 2023. He said it was hard for him to pinpoint exactly why he signed up, but didn’t think money was a major factor for him.

He said he previously served as a prison guard and, like Michael, claimed fighting for Russia was not a political choice.

He chose to fight for Russia because he felt it “has the upper hand in military strength.”

That view is not uncommon in China.

Maria Repnikova, an expert on Chinese and Russian politics at Georgia State University, said state media coverage in China leans towards a pro-Russia stance. “The Chinese outlets’ coverage of the war has significant impact on public perceptions of this ongoing invasion,” she said.

Some Chinese fighters have adopted language commonly deployed by the Kremlin, expressing their desire to “go against Nazi fascism” and referring to the war as a “special military operation” in public posts on Douyin, seen by CNN.

While they may not have caught the world’s attention until now, seeing Chinese fighters with buzz cuts sharing daily experiences from the frontlines and engaging in live chats with fellow fighters was commonplace on Chinese short video platforms. Their account handles often featured Chinese and Russian flags and CNN tracked several of their IP addresses to Russia and Russian-occupied territories in Ukraine.

But shortly after Zelensky raised the issue of Chinese fighters on the Russian frontlines with Beijing last week, many of those social media accounts were blocked.

The Russian recruitment ads, however, are still widely available on China’s tightly-controlled internet.

Michael was one of those Chinese fighters regularly sharing his experiences on Chinese social media, but he said was restricted from posting before the latest round of censorship. He believes the sweeping ban was because of his public comments detailing his mistreatment in the Russian military.

The other fighter, who returned to China in late 2024, said he discovered he was now prohibited from leaving the country last month, when he was stopped before a planned trip abroad. He suspects the travel ban is connected to his previous service in Russia. Chinese fighters on both sides

There have been Chinese fighting on both sides of this war, but those who chose to fight for Ukraine seem to have one thing in common: they spent time outside of China. Most of them believe they are motivated by ideology rather than money. Jason, who was born in China, moved to the United States during his high school years.

He claimed that in May 2023, he quit his master's program in computer science at a college in the United States to join the Ukrainian International Legion in Lviv, a city in western Ukraine. CNN has seen his Chinese passport and enlistment contract.

The infantryman at the time stated that he desired to be even more active in combat after spending four months evading shells in trenches and foxholes. He applied to transfer to an assault company, but said he was turned down because the Ukrainian commander was suspicious about his nationality.

Reflecting, a year after returning to the US, he said that was a “pity,” but he understood the suspicion because “China and Russia are pretty close.”

China’s threat to one day take Taiwan was a motivation for Jason to fight with Ukraine.

For the 27-year-old, the cause of the autonomous island, which China's Communist Party claims as its own and has pledged to seize by force if necessary, is deeply personal. He said his great-grandfather was a Nationalist soldier who lost his life in the fight against the Communists in the late 1940s during China’s civil war. Taiwan served as the Nationalist government's last stand. He hopes the fact he went to fight for Ukraine would give people in Taiwan a “sense of hope that someone would come to help,” if China were to invade.

I think most of the Chinese people are being brainwashed for a long time, he said.

Sophie, a PhD student from a top-tier Chinese university, is currently waiting for approval to join the Ukrainian International Legion. CNN has access to her application materials and passport. She told CNN that she "used to be pretty indifferent to politics," but after spending a year studying abroad in Europe, away from China's Great Firewall and its pervasive online surveillance, her perspective changed.Ukraine should acknowledge China’s efforts and constructive role in seeking a political solution to the crisis,” said Lin in a news conference on April 9.

China’s quick move to censor the social media accounts of Chinese fighters in Russia is to have been expected, according to Maria Repnikova, the Georgia State University expert. She stated, "The censorship of mercenaries is not surprising since the capture was a big scandal." Repnikova stated that the fact that recruitment ads were not censored in China and remain available was likely more of an "oversight" than "strategic" because the pro-Russian viewpoint in such videos is "just entwined with the narrative of Russia fighting well." Despite the fact that social media has unquestionably played a role in the recruitment of Chinese fighters, Michael and Jason may have fought on opposite sides of this war, but they have a shared experience: the reality of war, they said, was much worse than they ever expected.

Michael stated, "It's incredibly brutal, far beyond what anyone can imagine." CNN’s Victoria Butenko contributed reporting.