Demonstrations have been held on an almost weekly basis since July after authorities denied most opposition candidates registration in the elections for city parliament next Sunday.
Russia's opposition held a new protest march in central Moscow on Saturday, despite a ban by authorities, a week before controversial regional polls in the capital.
Moscow prosecutors warned that the latest rally, called by Kremlin critic Alexei Navalny on part of the city's Boulevard Ring, was not authorised and participants would "bear responsibility."
Ahead of the rally on social networks, Muscovites shared a photo of water cannons allegedly stationed along the route of the protest, dubbed the "March against political repressions."
Opposition politicians had requested permission to hold the march but were turned down.
In the past, the Moscow polls have generated little public interest.
But this summer they have spiralled into the biggest political crisis since the wave of protests in 2011-2012 against Vladimir Putin's return to the Kremlin.
Authorities have launched a wide-ranging probe into "unrest" which could lead to long prison sentences for a number of suspects and made thousands of arrests.
Another probe has been launched against Navalny's anti-corruption foundation, which has produced numerous videos alleging massive graft among officials at City Hall run by Putin's ally, mayor Sergei Sobyanin.
Many of the candidates were told the signatures they gathered to qualify were invalid, with Putin alleging they were "falsifications."
"Election committees found that their (signature) lists had ... people who had died long ago," he said last week.
But opposition candidates, such as politician Ilya Yashin, hit back, accusing Putin of lying and appealed this week to Russian Supreme Court to have his candidacy reinstated.
On Wednesday, Yashin was detained for the fifth time since July for violating rules on public gatherings.
Another candidate Lyubov Sobol, an associate of Navalny, was assaulted near her home Thursday.
According to OVD Info, an independent monitor of arrests and other politically-tinged persecution, police detained some 2,700 people at this summer's demonstrations.
In addition, there are multiple criminal cases against participants on charges such as "mass unrest" and "violence against police."
At least two couples who took their children to the protests have been threatened with losing parental rights.