Pussy Riot
Activists wear masks with a tape pasted over their mouths in support of members of the female punk band Pussy Riot (Reuters)

Russian prosecutors have launched a fresh criminal case into the two unknown members of Pussy Riot who escaped police after performing a protest song against President Vladimir Putin in Moscow's Christ the Saviour Cathedral.

The announcement came after Nadezhda Tolokonnikova, 23, Maria Alekhina, 24, and Yekaterina Samutsevich, 29 were found guilty of hooliganism motivated by religious hatred or hostility for the protest, and were sentenced to two years in prison by a Moscow court.

"We have launched a separate criminal case against the unknown members of the 'Pussy Riot' band, and are seeking to establish their identities," a police spokesperson told the Interfax news agency.

An interior ministry spokesperson told another agency, RIA Novosti, that the criminal case was ongoing and a search was under way.

The sentence provoked a national and international outcry - even among members of Putin's entourage and Russia's top Orthodox clerics.

Tikhon Shevkunov, considered Putin's spiritual counsellor, said that his church has forgiven the punk rockers after their "punk prayer" in Moscow's main cathedral.

"We did forgive them from the very start. But such actions should be cut short by society and authorities," said the cleric, who heads Moscow's Sretensky Monastery.

"We are simply praying and hoping that these young women and all these people shouting in front of the court building, committing sacrilegious acts not only in Russia but in other countries, realise that their acts are awful," another cleric, Archpriest Maxim Kozlov said.

"Despite this, the church is asking for mercy within the limits of law."

Pussy Riot's lawyer, however, said the band would not seek clemency from Putin.

"Our clients will not ask for a pardon," Nikolai Poklozov said. "Literally this is what they said: 'Let me go to hell with their pardon'."

Among the musicians and pop stars calling for the Pussy Riot girls to be released was Madonna, who has condemned the two-year jail sentence as "inhumane".

"Even if one disagrees with the location or how they chose to express themselves, the sentence is too harsh and is inhumane," Madonna wrote on Facebook.

"I call on all those who love freedom to condemn this unjust punishment. I urge artists around the world to speak up in protest against this travesty. They've spent enough time in jail. I call on all of Russia to let Pussy Riot go free."