MOSCOW -- Three Russian feminist rockers rejected charges of hooliganism for performing a "punk prayer" in Moscow's main cathedral against Vladimir Putin's return as president as a trial against them opened in earnest on Monday. The charges could carry a punishment of up to seven years in prison.

The three members of the Pussy Riot band -- Nadezhda Tolokonnikova, 23, Maria Alekhina, 24, and Yekaterina Samutsevich, 29 -- have been in custody for five months since their February stunt. Their prosecution has caused a sharp public divide and drawn protests from rights groups who have declared them prisoners of conscience.

The trial began July 20 but the first sessions were devoted to procedural issues. On Monday, with the court turning to the substance of the case, Tolokonnikova and other defendants said in statements read by their lawyer that their goal was to express their resentment over Russian Orthodox Church Patriarch Kirill's support for Putin's rule.

They pleaded not guilty to the official charges of hooliganism driven by "religious hatred." Tolokonnikova said she felt sorry if some of the believers felt insulted by their act, but that they didn't mean to offend anyone. It wasn't clear how long the trial might last, but a court has recently ruled that the women should be kept in custody for another half-year. Two other participants in the performance haven't been identified and remain at large.

Here is a look at what the women did and background on the case:

THE "PUNK PRAYER"

Two weeks before March's presidential election five women dressed in brightly colored miniskirts and balaclavas -- masks that cover their faces entirely and leave only the eyes uncovered -- and took over the church's pulpit for less than a minute. They high-kicked and danced around while singing a song pleading "Virgin Mary, drive Putin away!" that also contained diatribes against the top Orthodox clergy. They bowed and blessed themselves as security guards arrived to take them out. The performance was videotaped and immediately became an Internet hit. The act followed a series of other recent performances by the group, including one from atop a bus and another one from a jail roof. Shortly before their church stunt, they became an Internet sensation for a song titled "Putin Chickens Out" from a spot on Red Square used in czarist Russia for announcing government decrees.

THE CHURCH

The Christ the Savior Cathedral, Moscow's main orthodox cathedral, was consecrated in 1883 to mark the Russian victory over Napoleon. It was blown up in 1931 as part of Soviet dictator Josef Stalin's anti-church campaign, and a plan called for building a giant Palace of Soviets in its place, complete with Stalin's statue perched on top. That plan was delayed by swampy ground at the site and then abandoned for good when World War II began. The site was turned instead into a sprawling outdoor swimming pool. After the Soviet collapse, the towering church was rebuilt with the help of public donations and was consecrated in 2000. It has since served as Moscow's main Orthodox cathedral, becoming a symbol of the restoration of the Orthodox Church's power.

THE RUSSIAN ORTHODOX CHURCH'S RESPONSE

Patriarch Kirill has condemned the rockers' act as "blasphemous" and denounced those believers who called for the church to forgive them. His stance reflects the church's growing clout and has raised concerns about its close connections to the government and its growing influence over decision-making.

PUBLIC DIVIDE

Russia's leading liberal politicians and some of the nation's most prominent cultural figures have strongly protested the trial and criticized the church for supporting the criminal case instead of showing clemency. Amnesty International has called the three women prisoners of conscience. At the same time, some Orthodox groups and many believers are urging strong punishment for an action they consider sacrilegious. A poll conducted in Moscow earlier this month found that half of respondents oppose the trial while 36 per cent support it. The rest were undecided.

THE KREMLIN'S STANCE

Putin has avoided comment on the case, but many commentators believe that he has given his blessing to the prosecution of the three rockers as part of a crackdown on dissent following unprecedented protests in Moscow against his 12-year rule. Prime Minister Dmitry Medvedev said that it's up to the court to issue a verdict, but noted that some nations have even tougher punishment for that kind of action.