I read on https://thehill.com/homenews/ap/ap-international/ap-ukraines-zelenskyy-says-2-chinese-were-caught-fighting-alongside-russia/ that some Chinese citizens may be present in the Russian army and fight in Ukraine.
Can Chinese citizens legally enroll to join the Russian army and fight in Ukraine?
I'd like to know the Chinese legal stance on it.
Apparently yes. It's not easy to prove a negative, but articles about this have not said it's illegal, so the only reasonable explanation is that it is not illegal (i.e., this is an argument from silence).
E.g.:
China has rejected Ukrainian claims that "many" Chinese citizens are serving in Russian military units after two Chinese were captured on the battlefield in Ukraine's eastern Donetsk region.
There is no basis for this claim, Foreign Ministry spokesman Lin Jian said. He added that the Chinese government has consistently advised its citizens to avoid areas of armed conflict and to refrain from participating in military activities on either side.
(emphasis mine)
Notably Russia does allow foreign nationals to join its armed forces, and there are also foreigners fighting on the Ukrainian side. This, together with the fact that it's possible to gain citizenship in some countries "by shedding blood" for that country's armed forces, suggests that there are few countries that prohibit their citizens from fighting in another country's army. (Singapore is an exception.)
