Garry Kasparov, leader of Russia's opposition United Civil Front arrived at the headquarters of the FSB, successor to KGB intelligence service, on Friday (April 20). Kasparov has been served with the summons from the FSB, after he was arrested and fined for public order offences at the protests against President Vladimir Putin. "I think it is an important moment for Russia's political, civil and jurisdictional systems, because there is an attempt to make any kind of political activity a state crime. On the other hand, we should understand what is happening. It is some kind of supplementary examination and at least we will find out how the prosecutor's office via the FSB is trying to find evidence of criminal activity in critical remarks against the authorities," Kasparov told reporters before his meeting with FSB officials. The investigation into the former chess grandmaster came as a Kremlin spokesman conceded that Russian police who broke up opposition protests with batons last weekend had over-reacted. Riot police detained hundreds of protesters, including Kasparov, when they tried to hold a banned march in Moscow on Saturday (April 14). Police beat and kicked anti-Kremlin protesters in St. Petersburg the next day. In Moscow on Thursday (April 19), a senior activist from Russian human rights group Memorial, called on European leaders to issue travel bans on some of the Russian officials he said were responsible for ordering force to be used against protesters.