Pussy Riot
Tolokonnikova, Samutsevich and Alyokhina, members of female punk band "Pussy Riot", attend their trial (Reuters)

Russian state prosecutors have demanded that the feminist punk band Pussy Riot should spend three years in prison for staging a controversial protest against President Vladimir Putin at Moscow's Christ the Saviour Cathedral.

Nadezhda Tolokonnikova, Yekaterina Samutsevich and Maria Alyokhina entered the cathedral wearing masks, climbed the altar and chanted a song which implored the Virgin Mary to "throw Putin out" before they were arrested.

"The actions of the accomplices clearly show religious hatred and enmity," state prosecutor Alexei Nikiforov said in closing arguments in court where the trio are on trial for hooliganism motivated by religious hatred. "Using swearwords in a church is an abuse of God."

During a concert in Moscow, Madonna added her voice to those of other international artists, such as Red Hot Chili Peppers and Jarvis Cocker, who have appealed for leniency.

"I am against censorship and throughout my whole career I've always promoted freedom of expression, freedom of speech. So obviously, I think that what happened to them is unfair," Madonna said.

The singer, who has been cited as an inspiration for the band, said jail time would be a "tragedy".

"Art should be political. Historically speaking, art always reflects what's going on socially. It's hard to separate the idea of being an artist and being political," she added.

Leading British rock musicians such as The Who guitarist Pete Townshend, Cocker, Alex Kapranos of Franz Ferdinand, former Smiths guitarist Johnny Marr, Corinne Bailey Rae and Neil Tennant of the Pet Shop Boys have signed a letter, published in The Times, urging a fair trial - something that seems to have ben denied them, say critics.

Putin himself has urged the court not to judge the women too harshly.

"There is nothing good in this," Putin told journalists at the end of a one-day trip to London to meet David Cameron and watch the Olympics judo.