Candidates backed by the opposition's tactical voting campaign were set to beat out the ruling party for several Moscow city council seats after independent politicians were barred from running despite weeks of massive protests.
Magomet Yandiyev of the party A Just Russia was defeating Valeriya Kasamara, the candidate backed by the ruling United Russia party, in a closely watched downtown district with more than half of the ballots counted on Sunday night, according to data from the public electoral observation headquarters.
In addition, the head of the Moscow branch of United Russia and the incumbent head of the city council were reportedly losing to communist challengers Sergei Sevostyanov and Alexander Yefimov in their districts.
In a fourth district, a ruling party candidate was trailing independent Darya Besedina, according to observers.
Municipal deputy Ilya Yashin, who was barred from the city council race and kept in jail for 42 days as the protests unfolded, had backed Mr Yandiyev in his district as part of a "smart voting" campaign against United Russia. A Just Russia is one of the "system opposition" parties that rarely challenge the Kremlin line in parliament and other bodies.
Speaking to the Telegraph and other media after casting his own ballot, he called on supporters of the embattled liberal opposition to vote "not with your heart, but with your head" to help second-choice candidates edge out ruling party competitors.
"If we can get at least a nominally independent majority, that will give us a chance to control budget spending" and stop Moscow's Kremlin-backed mayor from "treating it like his own wallet," he said.
He also said falsifications could quickly erase any smart voting victories.
Preliminary results suggested that United Russia would suffer an embarrassing defeat in the eastern region of Khabarovsk, which would become the first province where another party controlled the executive and legislative branches as well as municipal organs.
The Liberal Democrat party, in fact a nationalist faction, was poised to take a majority in the city and regional parliaments and send its candidate to the national parliament after winning the governor's seat last year.
United Russia candidates were nonetheless set to win numerous other races, including the acting head of Russia's second city St Petersburg, whose main rival suddenly bowed out a week before the vote.
Tens of thousands repeatedly took to the streets of Moscow in July and August after almost two dozen independent candidates were barred from the city council race on technicalities mostly involving the onerous paperwork and supporting signatures required to run.
Rather than compromise, the authorities doubled down. Baton-wielding riot police arrested more than 2,700 people, and five of them received prison sentences last week on trumped up charges of violence against police and participating in unsanctioned protests.
With few options left, opposition leader Alexei Navalny launched the controversial "smart voting" campaign for a list of registered candidates, mostly communists, that he believed had the best chances of beating United Russia.
Supporters have said the tactic would chip away at United Russia's monopoly on power, while critics have complained it would keep up the charade of free elections.
President Vladimir Putin dismissed a question about the number of candidates on the ballot while he was voting on Sunday, arguing that "in some countries there are 30, 50 or 100, the quality of their work doesn't change".
More than 10 people were arrested near city hall wearing t-shirts with the faces of jailed protesters. Among them were journalist and municipal deputy Ilya Azar and Pussy Riot member Maria Alyokhina.
United Russia's brand has become so toxic in the capital that its candidates all ran as nominal independents. But they still enjoyed perks like television time, appearances at public events and get-out-the-vote efforts. There were reports around the country of state employees, students and soldiers being forced to vote en masse, as in past elections.
Electoral observers in other regions reported dozens of violations including blatant ballot stuffing captured on video.
A poll at a demonstration last week suggested that up to two-thirds of protesters agreed with the "smart voting" tactic.
"United Russia is the party of crooks and thieves. We're all tired of them. We can't really do anything, but at least we can do this," architect and Yashin supporter Tatyana Krasheninnikova said after voting for Mr Yandiyev. "We have lots of information about their real estate … They got rich at the city's expense. The less people like this on the city council, the better."
Student Daniil Azarkevich said he would instead spoil his ballot in a "small protest" since "it's already decided who will win".
At a polling place in an outer district of Moscow, pensioner Yulia Gusarova said she had voted for United Russia municipal deputy Svetlana Volovets because the district had a "lots of factories, it's very active, and she supports all this".
But for many, anger with the authorities will continue to build regardless of the election results, Mr Yashin told the Telegraph at a polling place where a belly dancer with a peacock was helping to get out the vote.
"It's not about the Moscow city council, it's about injustice," he said. "People sense injustice, they understand that they are being humiliated and their opinion is being ignored, and it's not especially important what becomes the immediate reason for the protests."