The White House on Thursday said officials were "deeply disappointed and concerned" by the conviction of Alexei Navalny, a top Russian opposition figure who was sentenced to a five-year jail term on Thursday.
"The numerous procedural shortcomings in this case also reinforce our broader concerns about rule of law in Russia," Carney continued. "We urge Russia to allow for a fair and impartial appeal of the verdict."
The strong denunciation from the White House came amid discussions with Russian authorities over the return of Edward Snowden, the former Defense contractor who has been holed up at the Moscow airport since fleeing Hong Kong three weeks ago. American authorities have asked the Kremlin to turn over Snowden, who has admitted to leaking details about top-secret National Security Agency surveillance programs.
Putin and other Russian officials have painted Snowden as a human rights activist and are weighing his request for temporary asylum in Russia.
At the White House, Carney swiped at Russia's track record on civil liberties.
"We call on the Russian government to cease its campaign of pressure against individuals and groups seeking to expose corruption and to ensure the universal human rights and fundamental freedoms of all of its citizens, including the freedoms of speech and assembly are protected and respected," he said.
Navalny, a prominent Kremlin critic, was found guilty of embezzling $500,000 worth of timber from a state-owned company where he worked as an unpaid adviser.
He rose to prominence in Russia as a blogger, writing about corruption and frequently needling President Vladimir Putin.