MOSCOW, February 28. /TASS/. Russian Prime Minister Dmitry Medvedev has expressed deep sincere condolences to the near and dear of Russian opposition politician Boris Nemtsov, who has been killed in downtown Moscow, Medvedev’s spokeswoman Natalya Timakova said Saturday.

"Dmitry Medvedev believes that law enforcers should do everything possible to define the entire range of people involved in this violent murder of the well-known politician," Timakova told TASS.