A leaked Russian document has revealed that Russian soldiers received secret nuclear and chemical warfare training on Chinese soil, a disclosure that has unsettled Western capitals. According to a classified document obtained by Reuters, Chinese instructors trained Russian troops at secure military facilities on how to handle radiation and deadly chemical attacks, and also taught them how such weapons are used. The revelation is being seen as fresh evidence of just how deep military cooperation between Russia and China has become, and it raises fresh doubts about Beijing's repeated claims of neutrality over the war in Ukraine.
A secret order signed in August 2025
The document obtained by Reuters shows that Russian Defence Minister Andrei Belousov issued an internal order in August 2025. The order stated that, on the minister's instructions, a special Russian military delegation would travel to bases run by China's People's Liberation Army, or PLA, for specialised training. Russia may frame the move as necessary for its own border security, but the involvement of senior generals and top officials in such a covert mission suggests China is using the exercise to pull Russia deeper into its own strategic calculations. A mission this sensitive would typically require sign off at the very highest levels of government, which is why analysts believe such an arrangement could not have gone ahead without the knowledge of both governments. Beijing has repeatedly denied any such cooperation, but the leaked paperwork appears to directly contradict that denial.
A three week course inside a secret Beijing facility
What stands out most in the leaked material is the subject of the training itself. This was not ordinary weapons or tank drills. Last November, a highly secure military site in Beijing ran a special three week course focused entirely on radiological, biological and chemical protection, in other words, both defending against and using nuclear, biological and chemical warfare.
The documents describe how Russian troops sat through lectures delivered by a Chinese instructor, with a model nuclear reactor placed at the centre of the classroom to explain the finer details of nuclear technology. Soldiers were also trained in chemical reconnaissance and radiation reconnaissance techniques on both land and sea, along with practical methods for protecting bunker ventilation systems from toxic air and radiation during a potential nuclear strike.
European officials note that biological and nuclear warfare training is considered extremely sensitive and strategically significant for any military. The scale at which China appears to be promoting this kind of training has raised concerns that it may be laying the groundwork for a far larger and more dangerous confrontation. Training of this nature is typically shared only among the closest of military allies, which is why analysts see this as a marker of a deeper new phase in the Russia-China relationship.
200 Russian soldiers trained, then sent to the front
The timeline in the leaked intelligence reports has added to Western unease. According to the report, China trained around 200 selected Russian military personnel in this manner last November. Once the training was complete, these soldiers were deployed directly to the front to help secure Russia's borders, meaning techniques learned on Chinese soil are likely now being applied on an active battlefield.
When questioned on the matter, the European Union's foreign policy chief, Kaja Kallas, said intelligence networks and diplomatic channels had fully confirmed that the secret training took place on Chinese soil. She added that officials are now closely assessing how serious the military and strategic consequences of this could be going forward.
China calls it a smear campaign
Facing Europe's tough stance, Beijing moved quickly to defend itself, dismissing the allegations as a vicious plot to defame China on the world stage. China's foreign ministry said in a statement that its position on the Ukraine crisis has always been clear and neutral, and that the allegations are entirely false and fabricated. This is not the first time China has faced accusations of covert military cooperation with Russia, and as before, it has flatly denied them. Yet the leaked documents present a very different picture of the quiet military partnership playing out behind the scenes.
Russia distances itself too, says it needs no lessons from China
Interestingly, Russian officials were quick to offer their own denial. When Andrei Kartapolov, chairman of the Russian State Duma's defence committee, was asked about the secret training, he dismissed it outright as sheer nonsense and a fabricated story, adding pointedly that the Russian military does not need to learn anything new from China.
Russia's own internal review reports have also been candid about what they see as China's biggest weakness. These reports note that while China has advanced, modern weaponry, high-tech simulators and no shortage of textbook knowledge, it simply lacks real battlefield experience, something Russia, after years of active combat, has in abundance. That may explain why Russian officials seem reluctant to publicly treat China as an equal military partner, even as cooperation between the two countries appears to be quietly deepening on the ground.
What this could mean going forward
The episode makes clear that military cooperation between Russia and China is not limited to arms deals or diplomatic statements. It may now extend to sharing sensitive nuclear and chemical warfare know-how. Western governments are watching the fallout closely, and the disclosure could yet reshape how they approach the broader diplomatic balance between Moscow and Beijing. Despite repeated denials from both capitals, the leaked documents suggest that Russia-China military ties have moved well beyond rhetoric and into genuinely sensitive territory.
