Thousands of people have marched in Moscow to honour opposition politician Boris Nemtsov, who was shot dead in the Russian capital on Friday night.
Families, the old and young walked slowly, with many holding portraits of the opposition politician and former deputy prime minister who was shot dead while walking home from a nearby restaurant on Friday night.
They gathered at a point not far from the Kremlin before marching past the spot on Bolshoi Moskvoretsky Bridge where Mr Nemtsov was killed. Some were carrying portraits of him and banners saying "I am not afraid".
Mr Nemtsov's allies have accused the Kremlin of involvement and say it was a political killing linked to his opposition to President Vladimir Putin and Russia's involvement in the Ukraine conflict.
But President Putin condemned the murder as "vile" and vowed to find the killers.
Police said 21,000 people attended the march. The organisers put the numbers at tens of thousands, but attendance appeared smaller than the 50,000 people the opposition had hoped for.
Many people carried the national flag and flowers to lay at the scene of the killing, which is already piled high with tributes. A few were holding Ukrainian flags.
Some of the placards read: "These bullets in each of us", "He fought for our future" and "Heroes never die".
Several thousand people have also marched in St Petersburg.
The authorities have suggested the opposition itself may have been behind his shooting in an attempt to create a martyr and unite the fractured movement. His supporters have blamed the authorities.
The opposition leader's murder has divided opinion in a country where for years after the Soviet Union collapsed many yearned for the stability later brought by former KGB agent Vladimir Putin, Reuters reports.
A small but active opposition now says Putin's rule has become an autocracy that flaunts international norms after Russia seized Ukraine's Crimea peninsula last year, fanned nationalism over the separatist war in eastern Ukraine and clamped down on dissent.
National investigators who answer to the Russian leader offered a 3 million rouble reward, around $US50,000, for information on Nemtsov's death. They say they are pursuing several lines of inquiry, including the possibility that Mr Nemtsov, a Jew, was killed by radical Islamists or that the opposition killed him to blacken Mr Putin's name.
President Putin's opponents say such suggestions, repeated over pro-Kremlin media, show the cynicism of Russia's leaders as they whip up nationalism, hatred and anti-Western hysteria to rally support for his policies on Ukraine and deflect blame for an economic crisis.
"We are told on TV that a conspiracy by the West and those among us who have sold out to them are behind our poverty. People should throw away the TV set and go to protest," said Olga, 42, who declined to give her last name.
Some Muscovites have accepted the official line and appear to agree that the opposition, struggling to make an impact after a clampdown on dissent in Putin's third spell as president, might have killed one of their own.
"The authorities definitely do not benefit from this. Everybody had long forgotten about this man, Nemtsov ... It is definitely a 'provocation'," said one Moscow resident, who gave his name only as Denis.
- BBC, RTR