The group's aim Sunday was to have a flashmob enter the famous square wearing white ribbons, the color adopted as a symbol by the opposition movement. But would-be participants were unable to enter the square, told by police who had encircled the area that it had been "closed for repairs."
The opposition now plans to hold a similarly themed event on Sunday inside metro station Ploshchad Revolyutsii, situated under Red Square.
"In a week's time, we will stage a flashmob #WhiteMetro: we will decorate metro station Ploshchad Revolyutsii (and also its neighbors Okhotny Ryad and Teatralnaya) with white ribbons, flowers, stickers, balloons, signs and girls dressed in white," the group wrote on its Facebook page.
Eighty-five people were arrested on Sunday at the unsanctioned rally outside Red Square when demonstrators attempted to move the event to the Zero Kilometer monument on neighboring Manezh Square, RIA-Novosti reported. Those detained included a correspondent of online television channel Dozhd. All 85 had been released as of Monday morning.
The opposition group, which did not say whether it had applied to City Hall for permission to hold the White Metro event, wrote that protesters should not worry about police.
"Don't hesitate because of police — you can also decorate them with flowers and ribbons," the group wrote.
By midday Monday, more than 450 Facebook users had indicated that they would attend the event.