The global campaign to free Pussy Riot is gaining speed: Supporters of the punk provocateur band mobilize this week in at least a two dozen cities worldwide to hold simultaneous demonstrations an hour before a Russian court rules on whether its members will be sent to prison.

Friday's rallies will ride a wave of support for the three women who have been in jail for more than five months because of an anti-Putin prank in Moscow's main cathedral. Calls for them to be freed have come from a long list of celebrities such as Madonna and Bjork. Protests have been held in a number of Western capitals, including Berlin, where last week about 400 people joined Canadian electro-pop performance artist Peaches to support the band.

In one of the most extravagant displays, Reykjavik Mayor Jon Gnarr rode through the streets of the Icelandic capital in a Gay Pride parade this weekend dressed like a band member — wearing a bright pink dress and matching balaclava — while lip-synching to one of Pussy Riot's songs.

Amnesty International has called the women prisoners of conscience and begun collecting signatures by text message for a petition to be sent to the Russian government, while the U.S. State Department has repeatedly expressed its concern.

Although the band members and their lawyers are convinced that the verdict depends entirely on the will of President Vladimir Putin, and prosecutors have asked for a three-year sentence, activists hope their pressure will ease punishment or even free the women.

Putin has said the women should not be judged too harshly, but he risks appearing weak if they walk free.

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Feminist punk group Pussy Riot members, from left, Nadezhda Tolokonnikova, Maria Alekhina and Yekaterina Samutsevich sit in a glass cage at a court room in Moscow on August 8. (Alexander Zemlianichenko/Associated Press)

Nadezhda Tolokonnikova, Maria Alekhina and Yekaterina Samutsevich were little known before their brief impromptu performance in Christ the Savior Cathedral in February. Dancing and high-kicking, they shouted the words of a "punk prayer" asking the Virgin Mary to deliver Russia from Putin, who was set to win a third term in a March presidential election.

They were arrested on charges of hooliganism motivated by religious hatred, which carries a maximum sentence of seven years. Since then, they have been vilified by the state media — while winning over hearts abroad.

Madonna donned a balaclava during a concert in Moscow last week and had "Pussy Riot" written on her bare back. Yoko Ono sent a personal message to Samutsevich, saying that "the power of your every word is now growing in us."

Canadian performer Peaches has gathered 85,000 signatures in the past five days on a petition in support of Pussy Riot on the social action website Change.org. The Berlin-based singer also created a Free Pussy Riot video featuring supporters in masks.

A group of leading British musicians, including Pete Townshend of the Who and members of the Pet Shop Boys, published a letter in the Times of London ahead of Putin's visit during the Olympics to urge him to give the Pussy Riot members a fair hearing.

On Friday, activists in more than a dozen cities, from Moscow to Toronto, are expected to take to the streets at 2 p.m. Moscow time (1000 GMT), an hour before the judge is to issue the verdict. The protests are being co-ordinated by the defence lawyers.

Venues vary from the square outside the ornate Sagrada Familia Cathedral in Barcelona to the yard outside the Russian Embassy in London.

In Paris, the protest will be held on Stravinsky Square and led by 29-year-old Alexey Prokopyev from Russie-Libertes, a Paris-based organization formed in December to bring together Russians studying or working in France.

"Most people go to these rallies in Paris because we cannot be in Russia at the moment for various reasons — because of jobs, classes," said Prokopyev, who was born in the Soviet Union and has spent most of the past 17 years in France. "We all wish we were in Moscow now, but since we can't we do it in Paris."

Russie-Libertes also is helping to organize rallies in Marseille, Nice, Lyons and Montpellier.

Wearing balaclavas, activists protested earlier this month on the iconic Alexander III bridge, named after the Russian czar who was France's ally in the 1890s.