Three members of Russian punk protest group Pussy Riot have gone on trial, in a case that has divided Russia and inflamed the religious establishment. They were taken into custody in February after singing a song protesting against President Vladimir Putin in Moscow's main cathedral. The song outraged the Russian Orthodox Church. It accused them of blasphemy. Supporters say the case reflects the state's growing intolerance of government opponents. Nadezhda Tolokonnikova, Maria Alyokhina and Yekaterina Samutsevich caused outrage when they stormed onto the altar of Christ the Saviour Cathedral, and sang an obscenity-laced song that implored the Virgin Mary to "throw Putin out". The head of the Russian Orthodox Church, Patriarch Kirill, has said the act amounted to blasphemy. The women are facing the charge of hooliganism motivated by religious hatred or hostility and could face up to seven years in prison. But their treatment has caused disquiet among many Russians as two of the women have young children, and all three have repeatedly been denied requests to be given bail while awaiting trial. Pussy Riot made headlines around the world late last year when footage of their controversial public performances at Moscow landmarks such as Red Square attracted millions of viewers on the internet. More than 100 prominent Russian actors, directors and musicians have urged the authorities to release the three. Western musicians such as Sting and the Red Hot Chilli Peppers have also criticised the women's arrest. Activists have said the case indicates that President Putin, now serving a third term in office, is not heeding calls for him to be more tolerant of political opponents.