Madonna: prison for Pussy Riot would be a 'tragedy'
7 August 2012 Last updated at 12:08 BST
Madonna has spoken out in defence of the punk band Pussy Riot.
The three women are on trial on charges of hooliganism motivated by religious hatred, after storming a cathedral in the city and performing an anti-Putin "punk prayer".
In Moscow ahead of her concert on Tuesday night, Madonna said it would be a tragedy if they had to serve the maximum sentence of seven years in jail.
She said, "I think art should be political. Historically speaking art always reflects what's going on socially".
Madonna joins a number of Western governments, human rights groups and performers such as the Red Hot Chili Peppers who have criticised the prosecution of the women.