Five members of Pussy Riot—wearing brightly colored homemade ski masks and miniskirts—briefly seized the pulpit of Moscow's main Orthodox church, the Christ the Savior Cathedral, in February and chanted "Mother Mary, drive Putin away."
A video of the performance posted on the Internet shows churchgoers gazing on astonished as the women chant, high-kick and dance around from the pulpit, and then appear to bow and bless themselves as security arrives to remove them.
Three band members—Nadezhda Tolokonnikova, 23, Maria Alekhina, 24, and Yekaterina Samutsevich, 29—were arrested and face up to seven years in jail on hooliganism charges.
An investigator petitioned to keep them in prison while the police probe continues, and on Wednesday, a Tagansky district court judge ruled the three will remain held until July 24.
Their cause and the Russian Orthodox Church's harsh response have provoked public outcry.
Outside the court building, police detained about 20 people as dozens of the band's supporters whistled in unison, chanted anti-Kremlin slogans and clashed with Orthodox activists who called on the band members "to repent."
Pussy Riot gained notoriety in January for performing a song taunting Putin—who was then prime minister—from a spot on Red Square used in czarist Russia for announcing government decrees. Videos of their performances became instant Internet hits.
The band's "punk prayer" took place two weeks before March's presidential vote. Putin won a third presidential term despite a wave of massive protests against his rule.
The church says the women deserve to be prosecuted for their "blasphemous" performance from a place near the altar that no lay persons are allowed to enter, although thousands of believers have signed a petition urging the church to forgive the band.
Attorneys for the band members argued that they should be released because they have young children.
The German government's human rights commissioner, Markus Loening, said he was "dismayed" by the decision to extend the band members' custody and called for their immediate release.
"This decision is clearly directed against freedom of opinion and artistic freedom and, in view of the consequences of nearly four months of custody for the families and children of the women, absolutely disproportionate," Loening said in a statement.
Although church and state are separate under Russia's constitution, the Russian Orthodox Church has claimed a leading role in setting moral guidelines for society. Its growing prominence has caused concern among followers of minority faiths and nonreligious Russians.
Geir Moulson contributed to this report from Berlin.