Russia's Pussy Riot punk band gave a surprise performance at a concert by US rockers Faith No More late Monday as three of its young women members await trial for singing an anti-Putin song in a church.
Five women bounded on stage during a Moscow concert by Faith No More, wearing Pussy Riot's signature brightly coloured balaclavas and yelling an obscenity-laden song calling for a "riot in Russia".
They held up a banner with the date of the jailed women's next court hearing on Wednesday, when supporters plan to hold a street festival.
"Hurrah! We just performed with Faith No More," Pussy Riot wrote on its Twitter account, attaching a photograph of the five women holding up lighted flares.
Faith No More also posted a link to a video of the concert on its Facebook page.
The band's appearance was introduced with the sound of the Kremlin chimes. Afterwards Faith No More put on balaclavas and Pussy Riot T-shirts to sing their 1980s hit "We care a lot," video footage posted on YouTube shows.
But fans of the head-banging Californian band that reached its peak of fame in the early 1990s were divided on the stunt, with some booing and whistling at Pussy Riot's appearance.
Three young women from Pussy Riot have been detained since March and risk up to seven years in jail on hooliganism charges after they performed a protest song against Putin in Moscow's central Church of Christ the Saviour.
The Russian Orthodox Church responded to the song as an attack on the Church and later rallied thousands for a prayer service at which Patriarch Kirill said the women had desecrated holy relics.
Two of the performers in the church have not been detained, but it was unclear whether they were among the performers on stage with Faith No More. The radical feminist group says it has no fixed line-up.
Recently influential music and arts figures both in Russia and the West have slammed the women's treatment.
Last week, over 100 of Russia's best known actors, directors and musicians signed an open letter calling for the women to be released.
Paris's Palais de Tokyo contemporary art gallery is currently hosting an exhibition about Pussy Riot and a member of US hip-hop band Beastie Boys, Ad-Rock, performed at a fundraiser for the women in New York last month.