Yup, plenty of Soviet soldiers came from the sister republics. This was also true of Napoleon's army in 1812, though he killed his share of Frenchmen as well. These ones are Russian in that they're carrying a Russian flag, though their uniforms to me look a bit Soviet.
There's an immense Soviet statue in Almaty saying "Comrades, you cannot retreat because behind lies Moscow." Why on Earth should a Kazakh care about that?
Cheers,
John
Update:
https://youtu.be/-dy26HE28Gc