Madonna, who had already voiced her support for the Russian punk band Pussy Riot, on Saturday joined a chorus of celebrities in slamming a jail sentence handed down in Moscow to three women from the group over a protest against President Vladimir Putin.
"I protest the conviction and sentencing of Pussy Riot to a penal colony for two years for a 40-second performance extolling their political opinions," Madonna said in a statement.
The three women were convicted in a Russian court of hooliganism motivated by religious hatred for performing a "punk prayer" in a Moscow cathedral in which they called on the Virgin Mary to rid Russia of Putin.
British singers Sting and Paul McCartney have also shown support for the Pussy Riot band.