A police officer detains a demonstrator in downtown Moscow, Thursday, March 31, 2011.
Riot police in Moscow have forcefully detained about 25 protesters who unfurled an anti-government banner at an unauthorized demonstration.
Thursday’s demonstration was the latest in a series of actions that Russian opposition figures call at the end of every month with 31 days.
The number corresponds with Article 31 of the Russian Constitution, which guarantees freedom of assembly.
(AP Photo/Sergei Savostyanov)