European nations, the US and some celebrities have condemned the jail sentences handed to three young women from the punk band Pussy Riot for their role in a song criticising Vladimir Putin, the Russian president.
Catherine Ashton, the European Union's foreign policy chief, said the two-year sentences given to Nadezhda Tolokonnikova, 22, Marina Alyokhina, 24, and Yekaterina Samutsevich, 30, were "disproportionate" to the crime.
The sentencing to corrective labour is the harshest possible for first-time female offenders.
The trio stormed the altar of Moscow's Christ the Saviour Cathedral in February wearing bright ski masks, tights and short skirts and sang a "punk prayer" urging the Virgin Mary to rid Russia of Putin.
A judge who read the verdict on Friday said they had been found guilty of "hooliganism motivated by religious hatred".
Ashton said the punishment would add to the intimidation opposition activists are facing in Russia.
"Together with the reports of the band members' mistreatment during pre-trial detention and the reported irregularities of the trial, it [the verdict] puts a serious question mark over Russia's respect for international obligations of fair, transparent and independent legal process," Ashton said.
"This case adds to the recent upsurge in politically motivated intimidation and prosecution of opposition activists in the Russian Federation, a trend that is of growing concern to the European Union," she said in a statement.
Angela Merkel, Germany's chancellor, said the sentence was "excessively harsh" and "not compatible with the European values of the rule of law and democracy to which Russia, as a member of the Council of Europe, has committed itself".
"A dynamic civil society and politically active citizens are a necessary precondition for Russia's modernisation, not a threat," she said.
Alistair Burt, the British foreign minister, said in a statement that the verdict "calls into question Russia's commitment to protect fundamental rights and freedoms".
The US, where protests against the sentences were held in major cities like New York, joined the chorus of condemnation, expressing disappointment over the verdict.
Josh Earnest, a White House spokesman, said in a statement: "While we understand the group's behaviour was offensive to some, we have serious concerns about the way that these young women have been treated by the Russian judicial system."
The Pussy Riot case, seen as a test of the extent of Putin's tolerance of dissent, has added to the strain already placed on relations between Moscow and European governments by their opposed positions on the crisis in Syria.
Although celebrities such as Madonna, who had spoken out against the charges previously and branded "an ex-whore" by Russia's deputy prime minister, did not comment on Friday, others took to Twitter to voice their concern.
Rocker Bryan Adams tweeted "Outrageous ... Russian singers jailed just for speaking their mind?"
Shortly after the verdict was read, chess maestro Gary Kasparov joined protesters in Moscow who carried placards reading: "Free Pussy Riot".
Amnesty International said the trial was politically motivated and the women were wrongfully prosecuted for a legitimate, if potentially offensive, protest action, adding that the verdict was "a bitter blow to freedom of expression" in Russia.
Amnesty "considers all three activists to be prisoners of conscience, detained solely for the peaceful expression of their beliefs", it said in a statement.
John Dalhuisen, director of Amnesty International's Europe and Central Asia Programme, said: "The Russian authorities should overturn the court ruling and release the members of Pussy Riot immediately and unconditionally."
Europe's main security and rights body, the Organisation for Security and Co-operation in Europe, said the verdict was part of a growing tendency towards curbing freedom of expression.
"I see a trend in various countries where the authorities, social and religious groups and courts are taking a more restrictive stance on content considered to be offensive, morally questionable or dangerous for children," said Dunja Mijatovic, the OSCE in Europe's Representative on Freedom of the Media.
"Most of the time it is a pretext for censoring content that is simply not mainstream and critical."