Russian authorities say they have detained some 20 people in downtown Moscow for “different violations.”
The announcement was made by the Interior Ministry on April 20.
ITAR-TASS news agency quoted an unidentified law enforcement source as saying most detainees were taken to police stations from the Red Square, where they tried to stage an unauthorized protest action.
Reports say many of the demonstrators were wearing white ribbons, the symbol of opposition to President Vladimir Putin.
Opposition activists have attempted to circumvent rules about unsanctioned demonstrations by saying they are doing nothing more than taking walks together.
Based on reporting by dpa, ITAR-TASS, and Interfax