Three members of the Russian feminist punk band Pussy Riot are facing two years in a prison colony after they were found guilty of hooliganism motivated by religious hatred, in a case seen as the first salvo in Vladimir Putin's crackdown on opposition to his rule.

Maria Alyokhina, 24, Nadezhda Tolokonnikova, 22, and Yekaterina Samutsevich, 30, were calmly defiant as a judge handed down the sentence, to cries of "Shame!" inside and outside court. Judge Marina Syrova said she rejected their arguments that they had not intended to offend religious believers but were protesting against the Orthodox church's support for Putin.

The case has galvanised Russia's anti-Putin protest movement and raised the international profile of their cause, with dozens of protests held worldwide.

British and American officials were quick to condemn what they described as a "disproportionate" sentence. The Foreign Office minister, Alistair Burt, said: "I am deeply concerned by the sentencing of three members of the band Pussy Riot, which can only be considered a disproportionate response to an expression of political belief."

A spokeswoman for the US state department said: "We urge Russian authorities to review this case and ensure that the right to freedom of expression is upheld."

Catherine Ashton, the EU's high representative, said she was disappointed by the verdict. "It puts a serious question mark over Russia's respect for international obligations of fair, transparent, and independent legal process," she said.

Putin has alleged that foreign powers are behind the protest movement against his rule, launched shortly after he announced last autumn that he was returning to the presidency.

Pussy Riot's supporters and opposition activists accused Putin of personally orchestrating the case against them. "They are in jail because it is Putin's personal revenge," said Alexey Navalny, the opposition's de facto leader. "The verdict was written by Vladimir Putin."

The three women were arrested in March after performing an anti-Putin "punk prayer" inside Moscow's Cathedral of Christ the Saviour. The case against them is seen as serving two functions: a warning to other dissidents, and an appeal to Putin's conservative base. Russia's growing campaign against gay rights is seen as a part of that effort, and on Friday Moscow's main court upheld a 100-year ban on gay pride rallies.

On Friday night, the Russian Orthodox church repeated its criticism of the band's "blasphemous" protest, which it said displayed "crude hostility towards millions of people" but called on state authorities "to show mercy to the people convicted within the framework of the law, in the hope that they will refrain from repeating blasphemous actions".

Dozens of protesters were arrested outside court, including chess grandmaster Garry Kasparov and leftist opposition leader Sergei Udaltsov. Hundreds more remained long after the court session had ended, shouting: "Russia without Putin!"

More than a dozen people have been arrested for taking part in a protest on 6 May against Putin, and could be jailed or fined under a new law against unauthorised demonstrations.

Navalny faces up to 10 years in prison after he was charged in a fraud case widely seen as an excuse to crack down on his activism. The country's rubber-stamp parliament has recently passed a law forcing nongovernmental organisations that receive international grants to declare themselves "foreign agents", and another that could prompt widespread censorship of the internet.

Protests in support of Pussy Riot were held around the world in New York, Vienna and dozens of other cities. The Royal Court theatre in London staged verbatim readings of the women's closing statement to the court to coincide with the verdict. Sir Paul McCartney, Madonna, and Björk are among the dozens of stars who have issued messages of support. Amnesty International and Human Rights Watch called the sentence a bitter blow to freedom of expression inside Russia.

Activists said the case has only strengthened the growing movement against Putin's rule. "Russia must stop being a laughing stock in the eyes of the world," said one woman protesting outside the court, who declined to give her name. "We must join civilised society. I really want to hope that our government will find common sense and stop showing itself in such a monstrous way."

Boris Akunin, one of Russia's most popular authors, said that the verdict had doomed Putin to "another year and a half of international shame and humiliation."

Other supporters were less optimistic. Tolokonnikova's husband Pyotr Verzilov said blame for the verdict rested with one man alone: "Whatever Putin wants, Putin gets."

In public statements made earlier this month, Putin had called for the women to be judged "not too severely". Prosecutors had asked for a three-year sentence.

The women remained defiant throughout the trial, issuing powerful closing statements that quickly entered the canon of Russia's dissident speeches. "We have won," Samutsevich said in her closing statement. "The whole world now sees that the criminal case against us has been fabricated. The system cannot conceal the repressive nature of this trial. Once again, the world sees Russia differently than the way Putin tries to present it." The women intend to appeal against the sentence.