Opposition politicians have been fighting to get on the ballot for September's elections to the Moscow city legislature as they seek to capitalise on growing public discontent over falling living standards and unchecked corruption.
But many observers say authorities have used spurious reasons to prevent popular allies of opposition leader Alexei Navalny from running for the Russian capital's legislature.
On Tuesday, Moscow election officials definitively rejected most of the prominent opposition figures from participating, citing lack of viable signatures.
The rejected candidates, including Navalny ally Lyubov Sobol and former MP Dmitry Gudkov, said the officials refused to look at proof that the signatures were rejected without grounds by unidentified "graphology experts".
At her meeting with the officials, Sobol said she was ready to present videos recorded by those whose signatures were rubbished, in which they reaffirm their support for her. But Sobol's arguments were ignored.
"You spat in the face of voters," she told the committee after they barred her from running. "You leave people no choice but to take to the streets."
Sobol had declared a hunger strike at the weekend demanding a transparent process of signature review and fair treatment of all candidates.
The opposition claims that many candidates loyal to mayor Sergei Sobyanin were registered without a stringent review despite violations.
The final list of candidates was set to be published on Wednesday.
Putin's spokesman Dmitry Peskov dismissed reports of foul play by electoral officials, saying only a court could determine that.
"If there are any objections or complaints, one can always go to court," Peskov told reporters. "So far, any other conclusions are nothing but rhetoric."
The opposition has vowed to stage daily protests demanding registration of candidates. Hundreds of people protested on Tuesday evening despite torrential rain.
"We should dig in our heels, we should resist," Yashin told hundreds of supporters in a furious speech at a rally Monday.
"I won't give up without a fight," said the 36-year-old who is the most popular candidate in his district according to polls.
Some 7.2 million Muscovites are eligible to vote to elect 45 lawmakers to the Moscow parliament, which is currently dominated by ruling party United Russia and rarely opposes Kremlin-allied mayor Sergei Sobyanin.