Thousands of Russians poured out on the streets and marched through central Moscow to pay their tribute to Putin-critic Boris Nemtsov, two years after he was fatally shot dead near the Kremlin.
On February 27, 2015, the former deputy prime minister was shot dead by four fatal gunshots while he was with his girlfriend.
Five Chehcen men are currently on trial for carrying out a contract hit, but the people who paid them have not been brought to justice.
Nemtsov's daughter has said the mastermind of the assassination remains unknown.
But Russians, clutching a bunch of red carnations, took to the streets to express their solidarity behind the family of the slain politician, the highest-profile murder since Russian President Vladimir Putin took charge in 2000.
"We came to pay tribute to the honesty and bravery of Boris Nemtsov," pensioner Galina Zolina told AFP, clutching a bunch of red carnations.
"We want to show the authorities that we haven't forgotten."
Some marchers even carried placards with "Russia without Putin" written on them.
Charismatic Nemtsov -- who went from Kremlin insider under Boris Yeltsin to one of Putin's fiercest foes -- was hit in the back by four fatal shots as he walked home across a bridge by the Kremlin with his girlfriend.
The march Sunday was permitted by the authorities but not allowed to include a makeshift memorial officials have repeatedly sought to dismantle at the spot Nemtsov was killed.
Some 15,000 demonstrators, organisers and AFP estimated, surrounded by a heavy police presence waved Russian flags and posters criticising the Kremlin and Moscow's intervention in Ukraine, which Nemtsov had fiercely opposed right up to his death.
"The march can maybe get the attention of the authorities," said unemployed biologist Alexei Kuznetsov.
"It might be able to influence the investigation, show that the case resonates in society even if the authorities try to ignore it."