Russians began voting in regional elections Sunday that Kremlin-loyal candidates are set to dominate, as police detained dozens of supporters of a jailed opposition leader who called for protests over pension reforms.
Plans to hike the retirement age have led to a rare outburst of public anger and seen President Vladimir Putin's approval ratings take a hit, despite some efforts to water down the changes.
But discontent is unlikely to translate into upsets at the ballot box, with serious opposition candidates in the highest-profile Moscow mayoral vote barred from standing.
Around 50 supporters of opposition leader Alexei Navalny, who is serving a month-long jail term over an earlier illegal protest, were detained ahead of the rallies, according to independent monitor OVD-Info.
Officers held dozens more as protests kicked off in eastern Russia and Siberia, with demonstrations set to take place in Saint Petersburg and Moscow in the afternoon.
Like Putin ahead of presidential polls in March, Moscow mayor Sergei Sobyanin has refused to take part in electoral debates but faces only nominal opposition and is all but guaranteed to win the vote in a landslide.
Authorities in the capital have organised festivals and food fairs at polling booths to drive up participation and lend legitimacy to Putin ally Sobyanin's next term as mayor.
"With all the imperfections of the electoral system... this is still the way of expressing your opinion, your satisfaction or dissatisfaction with what's going on in our city," Nikita Romashka, a 41-year-old dentist, told AFP after voting in Moscow.
The mayoral election of five years ago was the last time Russian politics came close to a major upset, with Navalny nearly forcing Sobyanin into a run-off.
Despite being behind bars, the opposition leader is continuing to make his presence felt.
"For 18 years, Putin and his government have stolen from the budget and squandered it on meaningless projects. Now the money's run out and we have to steal from pensioners to make ends meet," Navalny's team wrote on social media pages announcing the protest.
Google removed advertisements for the rally at the request of the Russian authorities, a close aide of the opposition leader said at the weekend.
Moscow had previously warned the US internet giant against "meddling" in the election.
Google's Russian office said it required advertisers to comply with local laws, in comments reported by news agencies.
Russians in various regions will be voting for their governors, local lawmakers and other officials.
In several Moscow polling stations there were scuffles between observers and police volunteers, OVD-info reported.
Supporters say mayor Sobyanin has transformed the city with billion-dollar renovation projects that include a showpiece central park and new pedestrian areas along with a string of new metro stations.
But critics argue these are a sop to a new urban middle class which has in the past protested against Putin's rule, while the Kremlin continues to crack down on political freedoms.