Moscow ( CNN ) -- An anti-government protest in Moscow turned violent Sunday , with some demonstrators clashing with police after they veered off their agreed-upon route . More than 250 people were arrested , including leading opposition figure Boris Nemtsov , leftist radical group leader Sergei Udaltsov and popular blogger Alexei Navalny , Moscow police told CNN . They were among the thousands that descended on the Russian capital for the latest demonstration denouncing Vladimir Putin , the nation 's current prime minister who was recently elected to a six-year term as president . He is set to be inaugurated Monday . As they marched , many chanted slogans such as `` Russia without Putin '' and `` Putin is a thief . '' A large number of demonstrators did not follow the route to Bolotnaya Square that their leaders had agreed to with Moscow authorities , instead stopping in front of a line of police and refusing to move . Clashes broke out , with some protesters throwing various objects -- including sticks and at least one flare -- at police . Authorities responded by `` clubbing demonstrators '' who briefly broke through police lines , the state-run RIA-Novosti news agency reported . One of its correspondents saw `` a male protester out cold after clashing with officers , '' while another reported eight officers arresting one demonstrator `` for the apparent crime of wearing a Guy Fawkes ' mask , '' the symbol of the vigilante hacking group Anonymous . Twenty officers were injured and three hospitalized in the clashes , according to RIA-Novosti , which added that those charged with assaulting police may face up to 10 years in prison if convicted . Itar-Tass , another official news agency , said four officers suffered cuts and wounds after having stones and bottles thrown at them and reporters . Police denied that they used tear gas as had been reported , according to RIA-Novosti . After the arrests , authorities slowly moved forward and moved everyone out of the area . Many protesters expressed disappointment that the event was not peaceful , with some saying they were angry at those who they felt had provoked a confrontation with police . Others who faced off with authorities voiced frustration that previous peaceful rallies had done little to forward their political aims . In March , Putin won the country 's presidential election with nearly 65 % of the vote , claiming victory amid allegations by independent polling monitors of widespread electoral violations . International observers said there was legitimate uncertainty about the vote , with chess champion-turned opposition activist Garry Kasparov accusing Putin 's supporters of `` massive fraud . '' Putin , the former KGB officer who has worked to both stabilize Russia 's economy and curtail dissent , held the presidency for eight years before term limits forced him to step down in 2008 . His election followed a series of anti-Kremlin protests in the wake of disputed parliamentary elections that took place in December .
Thousands protest against President-elect Vladimir Putin and his political allies . Some demonstrators veer off the agreed route and throw objects at authorities . State-media reports police `` clubbed '' some protesters ; police deny using tear gas . More than 250 are arrested , including key opposition figures , police say .