Ms Sobol was about to head to the unauthorised protest when she was taken by police
Russian opposition leader Lyubov Sobol has been detained ahead of an unauthorised protest in Moscow.
Ms Sobol was in a taxi about to set off for the rally when police officers dragged her into a black van, which swiftly sped off.
Protesters are gathering in the Russian capital after authorities disqualified a number of opposition candidates from standing in local elections.
Russian media reported a few dozen arrests across Moscow.
Some reports put that number much higher. OVD-Info, a group which runs a hotline for reporting detentions, said it had received at least 89 reports, and the number was “changing rapidly”.
Officers in riot gear have moved into the capital and warned people not to protest.
Ms Sobol, a lawyer and video blogger, is one of the candidates excluded from the local elections. She has been on hunger strike for 21 days, and called on others to join the unsanctioned protest on Saturday.
Authorities said she is being held for violating regulations for street demonstrations.
In July, Ms Sobol was dragged out of the electoral commission office on a sofa.