The Zamoskvoretsky district court in Moscow found the seven men and one woman guilty of participating in mass riots and using violence against police, an AFP correspondent reported.
Around one thousand people stood in protest outside the heavily guarded tribunal including opposition leader Alexei Navalny, as well as two members of the Pussy Riot punk band who complained they were barred from the courtroom.
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Prosecutors have asked for prison terms of up to six years for the eight defendants.
The trial was adjourned and scheduled to continue on Monday when sentences are expected to be handed down.
The defence team and human rights organisations have called the proposed sentences disproportionately harsh.
Human Rights Watch and Amnesty International have said that the charge of "mass riots" is inappropriate and called the case politically motivated.
The trial previously included 12 people but four were released after qualifying for a Kremlin-backed general amnesty in December because they faced a lesser charge.
Of the remaining eight, Sergei Krivov, 52, and Alexandra Naumova, 20, face the harshest punishment after prosecutors in December requested they be jailed for six years.
Also facing prison terms are protesters Andrei Barabanov, Alexander Polikhovich, Artyom Savyolov, Stepan Zimin, Denis Lutskevich, and Artyom Belousov.
Police said 50 people were detained outside the court as protesters chanted "Shame to the police!" and hung posters on a tree. A rights monitoring group, Ovdinfo, estimated that 110 people were detained.
"I was (at the protest) and... Any one of us could be on trial right now, it is terrible," said Nina, a middle-aged woman standing in the crowd.