Moscow: Russian anti-war presidential candidate Boris Nadezhdin said on Monday that a working group of Russia's Central Election Commission had found 15 per cent of the supporters' signatures he submitted to back his election bid to be invalid.
That figure, if confirmed, is three times higher than the allowable error rate and would provide grounds for the commission to disqualify Nadezhdin from running against President Vladimir Putin in March.
The commission will make a final ruling on the matter on Wednesday, Nadezhdin's spokesman said.
Nadezhdin said on Telegram that he would appeal to the Supreme Court if the commission refused to register him.
Nadezhdin last week presented the electoral commission with signatures from more than 100,000 supporters across Russia as part of his bid to get his name on the ballot paper.
On Friday, the commission said its initial analysis of the signatures showed some of those listed as Nadezhdin supporters were dead people.
Nobody expects Nadezhdin, 60, to win even if he is allowed to participate, given Putin's long dominance and control of the state.
But his campaign has captured people's attention because of his outright opposition to what the Kremlin calls its "special military operation" in Ukraine. Nadezhdin says Putin made a "fatal mistake" by launching it and has pledged to end the conflict via negotiation.