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.
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.
Amnesty International has declared the women prisoners of conscience and collected tens of thousands of petitions to be sent to the Russian government. So far, though, the human rights group said it has been blocked from delivering them. Two boxes containing 70,000 petitions were taken to the Russian Embassy in Washington on Tuesday, but a Russian diplomat carried them outside and dumped them on the sidewalk, Amnesty International spokeswoman Sharon Singh said.
"He did not want them anywhere on Russian soil," she said by telephone on Wednesday. Repeated calls to the embassy went unanswered.
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 at home and abroad.
About 20 supporters wearing colorful balaclavas held a brief protest on the steps of the cathedral on Wednesday, each holding up a letter to spell out "Blessed are the merciful" in Russian.
"This action was done in support of the girls," said Anna Tashina, 18, who was one of at least two protesters detained by police. "We wanted them to know that we are with them, that they haven't been forgotten."
Madonna also 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."
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 are expected to take to the streets beginning at 2 p.m. Moscow time (1000 GMT), an hour before the judge is to issue the verdict. The protests are being coordinated by the defense 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-Libertés, 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-Libertés 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.
Prokopyev said that he and his peers "want Russia to be a normal country" and be able to elect a president "who doesn't make the country where we were born a laughingstock."
In New York, Friday's protest will take place outside the Russian Consulate and later on Times Square.
"It's absurd that this case is being treated as criminal, while in any other civilized country that would be merely an administrative offense," said Xenia Grubstein, a 31-year-old journalist helping to organize the New York protest.
She said the hope was that the louder people speak out against the Pussy Riot case, the greater the chance that the verdict will be fair.
A protest is also planned in Washington, where last month punk rockers and arts activists rallied outside the Russian Embassy.
The U.S. State Department has expressed concern about what it called the "politically motivated prosecution of the Russian opposition and pressure on those who express dissenting views."
In France, Culture Minister Aurelie Filippetti last week issued a statement expressing concern that artistic freedom was on trial.
A German cross-party group of lawmakers sent a letter to the Russian ambassador calling the five months the band members have spent in custody and the possible prison terms "draconian and disproportionate" punishment.
"In a secular and pluralistic state, peaceful artistic activities—even if they may be seen as a provocation—should not lead to accusations of a serious crime and long prison sentences," the lawmakers said in the letter, which more than 100 members of parliament signed.
The international press has been full of critical reports from the trial. One of Germany's most influential magazines, Der Spiegel, featured the band on its cover with a picture of Tolokonnikova behind bars and the headline "Putin's Russia."
Greg Keller in Paris, David Rising in Berlin and Lynn Berry in Moscow contributed to this report.