Well, now we have it from the most official source possible: Foreign Minister Wang Yi who declared on Monday. “If the Russian side needs it, we will provide necessary assistance within our capacity". Considering the US rhetoric and imperial mindset which proclaims that "you are either with us or against us" it is pretty clear what such a declaration really means: China is putting the US on notice that in the current economic war Russia will have the full backing of China.
The Saker