The group in question is the Russian Imperial Movement; describing them as “white supremacists” seems rather a misclassification.

I can’t actually find anything about them on google prior to today, because it’s swamped by a million copies of this article. Simply based on their name though I tend to think that the “Russian Imperial Movement” might have an ideology which has something to do with Russian imperialism, rather than some sort of generalised “white supremacy”.