The United States said Thursday it was "deeply disappointed" over the jailing of Russian protest leader Alexei Navalny on fraud charges, calling the proceedings "politically motivated."
White House spokesman Jay Carney called on Moscow to allow for a "fair" appeal in the case and to cease its "campaign of pressure" against Russia's opposition.
Washington's condemnation of Navalny's treatment comes as relations between the United States and Russia are strained over the fate of US intelligence leaker Edward Snowden, who is staying in the transit area of a Moscow airport as he attempts to avoid extradition.
"The United States is deeply disappointed and concerned by the conviction of opposition leader and anti-corruption campaigner Alexei Navalny and his co-defendant," Carney said.
The spokesman said the 37-year-old Navalny and Pyotr Ofitserov had been sentenced on "politically motivated charges of embezzlement," noting "procedural shortcomings" in the case.
"We urge Russia to allow for an impartial and fair appeal of the verdict," Carney said, also calling on Moscow to "cease its campaign of pressure against individuals and groups seeking to expose corruption."
"Navalny's harsh prison sentence is the latest example of a disturbing trend of government actions aimed at suppressing dissent in civil society in Russia," he said.
Russian activists condemned the sentence for mass embezzlement as a blatant move to punish Navalny for opposing the Kremlin just as he was preparing to stand in Moscow's mayoral election.
Navalny, a fierce critic of Russian leader Vladimir Putin, was sentenced to five years in a penal colony on Thursday on fraud charges in connection with a 2009 timber deal.
President Barack Obama is due to visit Russia for the September 5-6 G20 summit in St Petersburg.
Obama and Putin agreed in June to hold a separate summit on September 3-4, just before the G20 talks, but White House officials have been coy about whether that meeting was still scheduled.
"I can say that the president intends to travel to Russia for the G20 Summit," Carney said. "I don't have anything to add to what we've said in the past about that trip."