Tens of thousands of people have marched through central Moscow to mourn opposition politician Boris Nemtsov, who was shot dead on Friday.
The mourners have marched to the bridge near the Kremlin where Nemtsov was gunned down.
Prominent Russian opposition figures have taken part in the march, including former Prime Minister Mikhail Kasyanov.
"Boris dedicated his whole life to making Russia a democratic state. He was exposing criminals and wasn't afraid to speak about it. That's why they hated him and dared to kill him."
The murder of 55-year-old Nemtsov came just a few hours after he conducted a radio interview in which he denounced President Vladimir Putin's policies as mad and aggressive.
He had been due to lead an opposition march on Sunday against Russia's actions in Ukraine, as well as the economic crisis at home.
Nemtsov's allies are pointing to the Kremlin for his murder.
Russian President Vladimir Putin has condemned the murder as "vile," and is vowing to find the killers.
Authorities are looking into a number of possible motives for Nemtsov's murder.
They include the possibility of attempting to destabilize the political situation in Russia, the internal situation in Ukraine and possible connections with Nemtsov's business activities.
A reward of just under 50-thousand US dollars is being offered for information leading to the killers.
