A senior member of a group of Russian volunteer fighters has stressed that its ultimate goal is to topple President Vladimir Putin's government.

The Liberty of Russia Legion has been carrying out attacks in western Russian regions near the border with Ukraine.

The group's political coordinator Ilya Ponomarev spoke to NHK via video link on Tuesday.

Ponomarev said the group is an official division of the Ukrainian armed forces, and has been fighting on the frontlines against Russian troops.

He also said the group is coordinating with the Ukrainians but acting independently, because Kyiv has promised the West that it will not attack Russian territory.

Ponomarev added that the group mainly consists of Russian military defectors who oppose Putin. He said it has the size of four battalions, while another anti-Moscow group, the Russian Volunteer Corps, has one battalion.

The political coordinator said thousands of people are applying to join the group but they have to undergo strict background checks because Russian agents are trying to infiltrate the group. He argued that this has become a bottleneck to accepting more members.

He conceded that although the legion does not currently have enough forces, its goal is to eventually reach Moscow. Ponomarev added that the Liberty of Russia Legion wants to have elites in the Russian capital understand that the war is lost and that Russian statehood is failing.