>>/46072/
> Russian troops

Al Jazeera uses term "Russian troops" very liberally, so reader may think that there are real Russian Army or at least some official entity. But looks like it is just a mercenary group, who is even less related to official Russian state than Blackwater (or how it is called now) to USA. 

These guys are completely illegal in Russia in terms of law, because being mercenary in Russia is a crime. But of course these mercenaries aren't mercenaries, and they don't even exist, we all know it.

> what other tasks they have

Foreigners are better in such conflicts because they more loyal than locals who always have interests in country. Foreigners also don't care about local population, so may do anything that locals wouldn't. So, I guess tasks are mostly about security of local leaders and small special operations.