The protest was staged by members of the Karachai minority ethnic group.
The demonstrators rallied for nearly three hours outside the republic’s Supreme Court building, chanting slogans hostile to the judicial panel's top judge.
Supreme Court Chairman Islam Burlakov has voided the outcome of the December municipal elections in one of Cherkessk’s southern districts amid allegations that the ballot was rigged. The initial winner was an ally of Karachayevo-Cherkessia’s President Mustafa Batdyyev and an opponent of Burlakov.
Burlakov was one of Batdyyev's unsuccessful rivals in the August 2003 presidential election.
Ethnic and political tensions have long been simmering in Karachayevo-Cherkessia.