@ali @aral

Irregular migration?!? Please define "irregular".

@the_andrey_x

To the best of my knowledge, participating in a war that violates internat. law does not automatically make a person a war criminal under case law. What is decisive is proof that the person has specifically violated the lawsofwar (Geneva Convention).
However, some national laws prohibit their citizens from participating in foreign wars.
Absurdly domestic involvement in the development, production, & (legal) sale of wmd to active foreign warring parties is not a criminal offense.