Kasparov was arrested because “he came and began to provoke police into taking harsh action, while knowing that the demonstration on Pushkin Square was forbidden,” a police spokesman was quoted as saying by Interfax news agency.
The former chess champion was taken to court in central Moscow and charged with shouting anti-government slogans.
“Today the regime showed its true colours, its true face,” Kasparov said during an adjournment.
“I believe this was a great victory for the opposition because people got through and the march happened.”
“March of Discontent”
Other Russia, a coalition of Kremlin opponents, organised the “March of Discontent” to protest against what they say is a squeezing of democratic freedoms under Putin.
|“What’s going on with the authorities? Have they lost their minds? What’s going on with this military operation?”
Mikhail Kasyanov, opposition leader
Kremlin supporters say Other Russia is trying to create instability ahead of the 2008 presidential election, when Putin has said he will step down.
Other Russia is thought to have marginal influence, as the vast majority of Russians support Putin, who has overseen rising incomes and political stability.
But the Kremlin and its supporters are wary of Other Russia, alleging the group is using street protests to stoke an uprising against Putin’s rule.
Mikhail Kasyanov, a former prime minister, was prevented from entering Pushkin Square, about 1km from the Kremlin, and many of his supporters were detained, the Interfax news agency reported.
“What’s going on with the authorities? Have they lost their minds? What’s going on with this military operation?” Kasyanov said afterwards.
Police drafted in
On Saturday, police, some wearing body armour, checked the documents of people passing through the square.
Insignia on the police vehicles showed that many of them had been drafted in from outside Moscow.
Russia’s mainstream liberal parties, which some critics say have been co-opted by the Kremlin, have largely kept their distance.
Grigory Yavlinsky, head of the Yabloko party, refused to participate in the Moscow march, saying in a statement that “the ideological and political composition of the these actions are unacceptable for Yabloko”.
Riot police earlier this year used truncheons to disperse protesters at opposition marches in St Petersburg and the city of Nizhny Novgorod.