Some 250 protesters attended an opposition Day of Wrath rally on Moscow's Teatralnaya Ploshchad on Sunday, which ended with several activists arrested, Interfax said.
The event was sanctioned, but some participants, including Left Front leader Sergei Udaltsov, were detained for trying to stage a march after it, the report said.
Udaltsov said about 20 people were briefly detained, while city police said there were about seven arrests. The figures could not be immediately reconciled.
