Millions of miles following the leader, following the party - (I don't know the artist)

Can't find a confirmation (e.g. a video recording of the performance or at least something crediting them as the performer), but the musical style really resembles the Korean People's Army State Merited Chorus, so I would assume they are the artist.

The artist is probably the KPA State Chorus, since they perform the majority of all the DPRK's revolutionary songs. Basically the DPRK's red army choir.