The Legion of Freedom for Russia, the Russian Volunteer Corps and the Siberian Battalion have on several occasions carried out raids against targets inside Russian territory.
Freedom for Russia brings together members from a wide range of ideological positions. The Russian Volunteer Corps has a clear connection to Russian right-wing extremism, which there are no signs that the relatively newly founded Siberian Battalion has.
The war in Ukraine
The groups are fully or partially part of the Ukrainian military. However, how many fight for them is unclear.
Learn more about what we know about the groups in the clip above.