MOSCOW, April 20 - RAPSI. The defense of the female punk group Pussy Riot, charged with public disorder in the Christ the Saviour Cathedral in Moscow will file an appeal on April 23 against the court ruling to extend their arrest, defense attorney Violetta Volkova told the Russian Legal Information Agency (RAPSI/ on Friday.

She added that the defense will file a petition to the Moscow Judicial Qualification Panel on the grounds that the arrest extension is illegal.

On Thursday the Moscow Tagansky District Court upheld the investigators' request to keep suspected members of the punk group Nadezhda Tolokonnikova, Maria Alyokhina and Yekaterina Samutsevich under detention until June 24. The defense has the right to appeal the arrest extension within three days of its pronouncement.

Pussy Riot was detained in early March for performing a "punk-prayer" in the Cathedral of Christ the Saviour. On 21 February, five masked members of Pussy Riot stormed the cathedral to perform a song by the main altar. The video of the performance then went viral and has sparked a public uproar.

Three of the members of Pussy Riot have been charged with hooliganism, a crime which faces up to seven years in prison.