Russian opposition leader Alexei Navalnyi was charged with embezzlement while the trial of punk-rock band "Pussy Riot" continued in Moscow. WSJ's Greg White reports. Photo: AP

MOSCOW—Three members of a feminist punk band pleaded not guilty in a trial that has become a nationally watched landmark in the struggle between Russian leader Vladimir Putin and an emboldened protest movement against him.

The drawn-out detention of the three women and the involvement of the Russian Orthodox Church in the case has made for the most politically charged trial since demonstrations calling for an end to Mr. Putin's domination of Russian politics began to gain momentum in December.

Under guard in the defendants' cage on Monday, band members, from left, Nadezhda Tolokonnikova, Maria Aliokhina and Yekaterina Samutsevich European Pressphoto Agency

The three pleaded not guilty on Monday to the criminal charge of hooliganism motivated by religious hostility for staging an anti-Putin "prayer" in Moscow's Cathedral of Christ the Savior.

Each defendant could face up to seven years in prison in the case. They were arrested after they and other members of the band known as Pussy Riot climbed onto the ambo, a platform usually reserved for priests, and sang "Our Lady, chase Putin out!"

The defendants, speaking from a courtroom cage, used the first day of trial testimony to define their stunt as a purely political protest against the Russian Orthodox patriarch's support for rule by Mr. Putin. The patriarch, the leader of the Russian Orthodox Church, has called their act blasphemous.

The church, to which most Russians belong, has been a pillar of support for Mr. Putin during his 12 years as Russia's president and prime minister.

The government prosecution of the women appeared to mark an end to the relative tolerance the Kremlin displayed during a winter of large antigovernment demonstrations. It also signaled an attempt by Mr. Putin to shore up his authority by appealing to his conservative and religiously observant base.

Until now, leaders of protesters who have been detained periodically have spent no more than a few weeks in jail. Some of the demonstrations were allowed to go on without any detentions of protesters.

In court Monday, a prosecutor called the stunt "a deliberate and carefully planned action to abase the feelings and beliefs of the followers of the Christian world and denigrate the spiritual foundations of the state." He noted that the band members wore neon-colored balaclavas to conceal their identity. Two other performers weren't caught.

The court then heard from the first of several witnesses who testified that the band's antics were satanic and had caused them suffering.

"I experienced bitterness and pain and feel it to this day," testified a church attendant, Lyobov Sokologorskaya. "It all looked like devilish skipping. They raised their legs and everything that was below their waists was visible. And that on the ambo, in front of the heavenly gates." Several other church workers who were present also testified that they were offended.

Defense lawyer Violetta Volkova read statements from the defendants saying their February protest was about the March 4 election, in which Patriarch Kirill I had signaled support for Mr. Putin, then prime minister, to return to the presidency. They said Russia is supposed to be a nonreligious state.

"We aren't enemies of Christians," defendant Nadezhda Tolokonnikova wrote in her statement. "Our motives are exclusively political." If anyone was insulted, she said, "then I am prepared to accept that we made an ethical mistake."

Speaking from the metal and clear-plastic courtroom cage, the defendant added: "We admit our political guilt, but not legal guilt."

The defendants, all in their 20s, had been led handcuffed to the courtroom, the same one where billionaire oligarch Mikhail Khodorkovsky was convicted of fraud two years ago.

Like that politically charged case, the prosecution of the women has polarized Russians.

Several dozen people gathered outside the courthouse, chanting "Victory!" and other slogans supporting the defendants. A smaller crowd nearby jeered them.

A group of leading conservative writers has called for tough punishment. A poll released on Monday by the independent Levada Center said 43% of Russians believe prison sentences would be too harsh, up from 32% who felt that way in April. Amnesty International said the prosecution is politically motivated and prejudiced by a series of denunciations of the women by leading politicians and clerics.

Defense lawyer Mark Feigin said he had no doubt the women would be convicted.

Prime Minister Dmitry Medvedev dismissed criticism of the case in a weekend interview with the Times of London. "Let us wait for the investigation to be over and the verdict of the court and then we can say if a crime was committed or not," he said.

Write to Richard Boudreaux at