Pussy Riot stars Nadezhda Tolokonnikova and Maria Alekhina have hit back at reports suggesting they have quit the Russian protest group, insisting: "We have not left."

The pair, who were released from a two-year prison sentence in December (13), had reportedly split from the punk collective to concentrate on their campaign to improve jail conditions in Russia.

An anonymous letter was posted on Pussy Riot's official Livejournal website last week (ends09Feb14) accusing the pair of getting "carried away with the problems in Russian prisons" and abandoning the "aspirations and ideals of our group".

The message added, "The mixing of the rebel feminist punk image with the image of institutionalised defenders of prisoners' rights, is harmful for us as (a) collective, as well as it is harmful for the new role that Nadia and Masha (Alekhina) have taken on."

However, the two women have now hit back, insisting they "never left" Pussy Riot and suggesting the online letter was not written by an official member of the protest group.

Tolokonnikova says, "I don't know who they are, these people who claim to be from Pussy Riot and write on social networks. We never left Pussy Riot."

Alekhina tells The New York Times, "(We are) still in contact with... the people we performed with."

The pair, along with third Pussy Riot member Yekaterina Samutsevich, were jailed for two years each in 2012 for performing a protest song against President Vladimir Putin at a church in Moscow. Samutsevich was freed in October, 2012 when her sentence was commuted.