Supporters of opposition politician Alexei Navalny have been gathering in some 20 Russian cities to back his bid to run in March’s presidential poll.
They are seeking to gather signatures needed to register him as a candidate to challenge Vladimir Putin.
However, election officials have already ruled Mr Navalny ineligible due to a corruption conviction which he says is politically motivated.
Mr Navalny is speaking at the gathering in Moscow.
He is widely regarded as the only candidate who has a chance of challenging Mr Putin, who is seeking a fourth term.
Russian socialite and TV presenter Ksenia Sobchak is standing in the election but some – including Mr Navalny – regard her as a “Kremlin stooge”.
Mr Navalny, 41, needs to be formally nominated by 500 people in 20 cities across the country.
He will hope securing the signatures will pressure the election commission into allowing him to run.
The BBC’s Sarah Rainsford has been attending the Moscow nomination meeting for Mr Navalny.
She said supporters at the meeting have been making speeches saying “at last the movement for change has a real leader” and “we demand he run for president. Without Navalny there can be no elections”.
One Navalny supporter named Maria, told Deutsche Welle journalist Mykhailo Komadovsky: “I personally have only one enemy, His name is Putin. Only Navalny can fight against him.”
Mr Putin, who refuses to mention Mr Navalny by name, still retains a massive approval rating and is almost certain to ease to victory in the election.
Mr Navalny led mass street protests against President Putin in the winter of 2011-12 and has served three jail terms this year alone for organising unauthorised anti-Putin protests.
The opposition politician insists he would beat Mr Putin in a fair fight.
In an interview with Associated Press last week, he said he would win “if I am allowed to run and if I’m allowed to use major media”.
He said: “Putin has nothing to say. All he can promise is what he used to promise before, and you can check that these promises did not come true and cannot come true.”