Police in Moscow have detained more than 1,000 people at a rally, in one of the biggest crackdowns in years.
Demonstrators were dragged away from the city hall as security forces used batons against the crowd.
People were protesting against the exclusion of opposition candidates from local polls. The opposition say they were barred for political reasons.
Some of the candidates banned from standing in the 8 September election had been detained earlier.
Officials disqualified about 30 people, saying they had failed to collect enough valid signatures to stand.
At least 1,074 arrests were made at the banned rally, officials say, while monitors reported 1,007 detentions.
Moscow’s Mayor, Sergei Sobyanin, has called the demonstration a “security threat”, and promised to maintain public order.
Anger is widespread among opposition supporters at the way the city is run and the ruling United Russia party.
Opposition leader Alexei Navalny, a fierce critic of President Vladimir Putin, was jailed for 30 days on Wednesday after calling for Saturday’s unapproved demonstration.
How Saturday event unfolded
Last Saturday, more than 20,000 Russians took to the streets, demanding fair elections, and dozens were arrested.
It is unclear how many people turned up for the new unauthorised rally on 27 July but the numbers seem to have been sharply down.
According to police, about 3,500 people gathered, including about 700 journalists.
Police in riot gear pushed back the crowd from barriers surrounding the mayor’s office in central Moscow, hauling off detainees to police stations.
A number of protesters could be seen bleeding while at least two members of the security forces reportedly received eye injuries from pepper spray.
Elections conduct in Russia
Local elections usually attract little attention in Russia.
The Moscow authority does not control the city’s budget or choose key official appointments, and previous votes have passed without major protests or press interest.
But this year some Muscovites are infuriated at what they see as brazen attempts to disqualify independent politicians from running.
Candidates were asked to collect 5,000 signatures to stand. This limit was made even harder to match because a signature “means volunteering one’s personal information for the government’s database of opposition supporters”, democracy activist Vladimir Kara-Murza wrote in the Washington Post.
Many candidates managed to meet the threshold but the electoral commission ruled some signatures ineligible, saying they were unclear or the addresses provided were incomplete, and barred the candidates from taking part.
Opposition groups say the authorities had no reason to rule them ineligible – claims that electoral officials denied. “We have no reason to doubt our experts,” commission member Dmitry Reut said, according to media reports.
Mr Navalny, who addressed the crowds last Saturday, is not one of the candidates, although he stood in Moscow’s mayoral elections in 2013 and won 27% of the vote in a result he disputed.
Ella Pamfilova, the head of the electoral commission, said the protests would not change their decisions. “It doesn’t matter, not even a bit of it,” she said, dismissing the demonstrations as “political”.
The authorities banned this Saturday’s rally on the grounds that there were threats of violence against the commission.
Police then raided the homes of several opposition politicians, and called them in more for questioning.