Moscow ( CNN ) In his first substantive comments since Kremlin critic Boris Nemtsov 's death , Russian President Vladimir Putin on Wednesday called the killing a `` disgrace '' and lashed out at what he called `` extremists '' and protesters . Nemtsov had been one of Putin 's harshest critics and had been arrested several times for speaking against the President 's government . The 55-year-old opposition leader was gunned down Friday night in Moscow as he walked across a bridge about 100 meters ( 330 feet ) from the Kremlin with his girlfriend , Ukrainian model Anna Duritskaya , 23 . His slaying spurred thousands to rally in his honor in Moscow , with many calling him a true Russian patriot at his funeral Tuesday . Nemtsov is n't the first of Putin 's critics to turn up dead , with others including Anna Politkovskaya ( who was fatally shot ) and Alexander Litvinenko ( who was poisoned ) . The Kremlin has staunchly denied accusations that it 's targeting political opponents or had anything to do with the deaths . The Russian leader has condemned Nemtsov 's killing and ordered three law enforcement agencies to investigate , the Kremlin has said . He also wrote to Nemtsov 's mother , saying he shared her grief , and promised to bring those behind the killing to justice . Yet those expressions came in Kremlin statements . Wednesday was the first day Putin spoke at length on the subject , remarks that were reported by state media outlets . Referring to `` the daring killing of Boris Nemtsov in the very heart of our capital city , '' he said , `` Russia should be made secure , at last , from the disgrace and tragedies of ( this ) kind . '' The President added , according to the official Tass news agency , `` The most serious attention should be paid to high-profile crimes , including those having political motives . '' No one has been arrested in connection with Nemtsov 's death , though Russia 's Federal Security Service chief Alexander Bortnikov did say there are suspects , Tass reported . The same agency , citing Russia 's Finance Ministry , said that investigators are looking for a car that belongs to a state enterprise that provides services to that ministry . Putin did n't identify any person or group that might be directly responsible . But Wednesday he took the opportunity to lay blame generally at what he called `` color technologies , '' an apparent reference to using mass street protests and overseas funding to try to overthrow a government . `` The actions of extremists are becoming more and more widespread , '' the President said . `` We are running into attempts of using so-called color technologies , from organizing illegal street protests to open propaganda ( expressing ) hatred in social networks . '' CNN 's Alla Eshchenko reported from Moscow , and CNN 's Greg Botelho wrote from Atlanta . CNN 's Laura Smith-Spark and Matthew Chance contributed to this report .
Opposition leader Boris Nemtsov was shot dead while walking near Russia with girlfriend . Vladimir Putin : Kremlin should be safe from `` disgrace and tragedies '' like Nemtsov 's killing . Kremlinn President criticizes `` extremists '' for use of `` illegal street protests '' and social media .