Opposition activists that included Left Front leader Sergei Udaltsov and opposition politician Boris Nemtsov gathered for an unsanctioned rally in Red Square in downtown Moscow on Sunday.
Several dozen people wearing white ribbons as the symbol of the Russian opposition are participating in the rally.
Udaltsov is talking to his supporters while police are not interfering in the action.
A police officer told RIA Novosti that the rally participants were not violating the law so far as they were not shouting any slogans.
The opposition has earlier announced plans to hold a White Metro flash mob on Sunday and decorated the Revolution Square metro station with white symbols. The police urged the demonstrators to break up and detained three people.
Tens of thousands of Russians protested against alleged electoral fraud in favor of Prime Minister Vladimir Putin’s United Russia at December 4 parliamentary polls. Smaller rallies also took place after Putin’s victory in the first round of March 4 presidential polls.