Notorious nationalist group The Other Russia boasted Friday of having disrupted a show by a Russian rock legend, unleashing pepper spray among the audience.
The attack was a response to musician Andrei Makarevich's alleged support of official Kiev in its standoff with pro-Russian separatists in eastern Ukraine, the group said on its website.
Makarevich's Yiddish Jazz show in Moscow on Thursday was disrupted for two hours, but eventually resumed at the audience's request, Interfax reported.
Police have opened a case on hooliganism charges, punishable by up to five years in prison, but reported no detentions as of Friday.
Makarevich, the frontman of Soviet-era underground rock icons Mashina Vremeni (Time Machine) and an affiliate of President Vladimir Putin, is one of few public figures in Russia to have taken an anti-war stance over Ukraine, performing a concert for Ukrainian children in a former war zone in August.
That show made Makarevich, 60, the target of a vicious smear campaign in state media.
The Other Russia, an unregistered party led by flamboyant writer-turned-politician Eduard Limonov, was vehemently anti-Kremlin in the 2000s, but has recently performed an ideological U-turn, siding with Putin over his alleged — but never confirmed — backing of Ukrainian insurgents.