Members of the Russian punk band Pussy Riot were sent to forced work camps in Mordovia (Nadya Tolokonnikova) and Perm (Maria Alyokhina). They are considered to be the worst of the Russian prison system.
Forced work is a penal variant of slavery that is at the very least rare in Europe, being a clear case of slavery, i.e. a crime against humankind.
As you probably know, the members of Pussy Riot are victims of an inquisitorial persecution by the fascist regime of Vladimir Putin and the Russian Orthodox Church.
Source: Sare Antifaxista[es].