Russian opposition figures: Ksenia Sobchak
The BBC looks at some of Russia's key opposition figures.
For years TV celebrity Ksenia Sobchak was identified as a glamorous, high-profile supporter of Vladimir Putin, but all that changed when she joined the opposition in December 2011.
Her opposition activism was triggered by the December parliamentary election, comfortably won by the pro-Putin United Russia party, but marred by complaints of irregularities.
The 30-year-old is the daughter of St Petersburg's first post-Soviet mayor, Anatoly Sobchak. His friendship with Mr Putin dated back to the 1980s, when he was a law professor in the city then called Leningrad.
Ksenia Sobchak studied political science but made her name as the host of Dom 2, a Russian equivalent of the reality TV show Big Brother. An active socialite, she earned the nickname "Russia's Paris Hilton".
Her decision to join the opposition in December has affected her career in the mainstream media, where state influence is strong.
Her talk show Gosdep was dropped from the Russian version of music channel MTV after just one episode, after she invited on the leading anti-corruption campaigner Alexei Navalny.
But she launched three politics shows on niche outlets that tend to favour the opposition. Her show Gosdep-2, on the social networking site Snob.ru, tackles hot topics such as the Orthodox Church's role in society and gay rights.
She is one of Russia's most popular bloggers and her Twitter account - xenia_sobchak - has more than 430,000 followers.
Her satirical spoof of Putin campaign videos, in the run-up to the presidential election in March, was a hit on the internet.
The original videos used young women to suggest that voting for Mr Putin was sexy - so Ms Sobchak mocked them in a spoof, where she looked bedraggled and abused.
"Now is not the time to rock the boat and we should rally round one leader," she said. But when she finished speaking she was shown to be bound to a chair, then gagged by thugs and bundled away.