A leading Russian opposition politician, former Deputy Prime Minister Boris Nemtsov, has been shot dead in Moscow, Russian officials say.
An unidentified attacker in a car shot Mr Nemtsov four times in the back as he crossed a bridge in view of the Kremlin, police say.
He died hours after appealing for support for a march on Sunday in Moscow against the war in Ukraine.
Russian President Vladimir Putin has condemned the murder, the Kremlin says.
President Putin has assumed "personal control" of the investigation into the killing, said his spokesman Dmitry Peskov.
Investigators said the murder could have been "a provocation aimed at destabilising the country".