This picture taken by a witness outside of the Pussy Riot trial shows armed police dragging chess grandmaster Garry Kasparov into a riot van.
Tweeter Olaf Koens, who took the snap, said: "This is the police wrestling with Garry Kasparov inside the paddy wagon [sic]. Are they beating him?"
The chess player retired in 2005 to become more involved in politics, especially opposing Vladimir Putin, and writing.
He formed the United Civil Front movement and joined several other anti-Putin groups but according to reports, support for his views in Russia is low.
Kasparov’s Facebook page confirmed the arrest, saying: "Garry Kasparov has just been arrested outside the Moscow courthouse where the Pussy Riot trial is taking place. He was not there to protest, simply to attend, and the police cornered him and dragged him into the police van. This photo shows the police assaulting him inside the van. We hope he is all right and we will provide updates when we have them."
Only a few hours earlier he posted this: "Statement from the Human Rights Foundation on Pussy Riot, including my comments.
"What is most frustrating about the considerable western reaction to this horrible farce is when the media talks about Putin and the Kremlin ‘losing a PR battle" with a punk rock band. What does Putin care about PR in the west? As long as the oil and gas keep flowing and the money keeps going from the treasury into the crooks’ pockets, they don’t care about anything else! As I’ve said many times, Putin and his criminal regime are a Russian problem for Russians to solve, but western hypocrisy about human rights gets tiresome when they could take serious measures instead of just talking.
"I am glad artists like Paul McCartney and Madonna are speaking out, but until Interpol and EU parliaments and American legislators take action to penalize Putin’s cronies for criminal, financial, and human rights violations, all the press chatter in the world makes little difference. Tell the young children of Tolokonnikova and Alyokhina that their mothers ‘are winning a PR battle’ while they sit in prison for three years for political protest!"
