Insider has obtained confidential documents showing that Russia and China are building a much deeper military cooperation than both admit.

For years, Beijing has claimed neutrality in Ukraine. These documents, for the first time, prove that China is fully involved in Russia’s war planning against Ukraine, in exchange for Russian battlefield experience—trading in artificial intelligence, electronics, drone production, and weapons technology. They also show that the two sides are jointly developing missile defense, drone attacks, armored vehicles, and programs to create jamming, hacking, and the physical destruction of Starlink.