|Can Anti-Putin Protests in Russia topple the "strong man" ?|
At least 500 other protesters were detained in the capital and across the country.
Most of the marches were illegal, organised without official permission.
TV pictures showed demonstrators chanting "Down with [Russian President Vladimir] Putin!", "Russia without Putin!" and "Putin is a thief!".
Alexei Navalny: Anti-corruption campaigner Alexei Navalny has long been the most prominent face of Russian opposition to President Vladimir Putin.
But he may be forced to abort his plan after his conviction by a Russian court of embezzlement, which would bar him from any candidacy.
He denies the accusations, and says his legal troubles are Kremlin reprisals for his fierce criticism.
Another issue which must be seen as extremely troubling by opposition forces in Russia and freedom of speech activists around the world are President Vladimir Putin's plans to create a major international news agency called Rossiya Segodnya, or Russia Today, is being seen as a significant move in Moscow's strategy to influence world opinion. But it has also raised concerns about further curbs on media freedom in Russia itself.
Mr Putin's decree liquidating state-owned news agency RIA Novosti and the Kremlin's international radio station, Voice of Russia, and replacing them with Russia Today came like a bolt from the blue.
Both RIA Novosti and Voice of Russia have been stalwarts of the media scene for several decades. They were founded way back in the Soviet past, in 1941 and 1929, respectively.
RIA Novosti has been a particularly valued outlet which, although state-owned, has reflected a diversity of opinion in some of its output. Its court reporting service RAPSI also recently won an award for, among other things, its live transmissions of the trial of opposition leader Alexei Navalny.
Pro-Kremlin commentator Sergey Markov wrote on Facebook that the agency's demise may be linked to its coverage of anti-Putin protests in 2012 and the apparent sympathy of some of its journalists for the opposition.
Rossiya Segodnya, or Russia Today seems likely, therefore, that it will complement the work of the state-funded foreign-language TV station, RT, which when it was launched in 2005 was also known as Russia Today.
The new agency will be a "huge machine for propaganda in the West", tweeted liberal website editor Roman Fedoseyev.
The most controversial aspect of Russia Today's launch was the appointment of Mr Kiselev as its director-general.
Known back in the 1990s as one of the faces of "independent journalism", Mr Kiselev has recently become notorious for his extreme and sometimes bizarre diatribes in his role as a top anchor on official channel Rossiya 1.
He has likened Kremlin opponents at home and abroad to the Nazis, used a Swedish children's TV show about toilet training to exemplify "Western values", and repeatedly demonised homosexuals.