MOSCOW — Russian opposition leader Alexey Navalny claimed the vote was rigged after an ally of Russian President Vladimir Putin narrowly won Moscow’s mayoral election.

Acting Mayor Sergei Sobyanin, appointed in 2010, received 51.3 percent of the vote, just avoiding a run-off, according to near-final official results released Monday. Navalny finished second with 27.3 percent of the vote.

“We regard this as a clear falsification,” Navalny said in televised comments. “I call on the Kremlin to hold a second round as should happen.”

The race pitted the Russian authorities against an opposition candidate in Moscow for the first time since allegations of voter fraud sparked a wave of protests in 2011 and 2012 in Europe’s biggest city. Navalny, 37, an anti- corruption activist and leader of the anti-Putin demonstrations, captured nearly twice the share of votes as expected.

Navalny supporters plan to protest in Moscow’s Bolotnaya Square, the site of earlier opposition rallies, this evening, Ekho Moskvy radio reported. The opposition candidate published exit polls that gave him 36 percent to 46 percent for Sobyanin.

“Such results increase the likelihood of mass street protests later today,” Vladimir Osakovskiy, chief economist for Russia at Bank of America Corp. in Moscow, said in e-mailed comments. The “very narrow margin of first round victory gives the opposition more reason to talk about ‘another stolen election,’” and will “add to market pressure on concerns over political risks,” he said.

Low turnout was responsible for an unanticipated surge by Navalny, according to Alexander Oslon, president of the Moscow- based Public Opinion Fund.

“That worked to Navalny’s advantage because his backers are enthusiastic and motivated,” said Oslon.

LOW TURNOUT

Direct gubernatorial elections were restored after tens of thousands took to the streets in the biggest demonstrations of Putin’s rule. He won 48 percent of votes in Moscow in his re- election last year, less than anywhere else in the country.

“It’s a great result,” Sobyanin, 55, said in televised comments. “We’ve met the test of fair elections: hard-won votes are worth far more than a few percentage points.”

About 26 percent of Muscovites turned out for the vote as of 6 p.m., which features another four candidates, the Interfax news service reported, citing Russia’s Central Election Commission. Sobyanin resigned in June to call the ballot.

Since taking over as mayor from Yury Luzhkov, who was forced out, Sobyanin, has sought to ease Moscow’s traffic congestion and revamp infrastructure such as public parks. He served as a deputy prime minister in 2008 to 2010 as Putin completed a four-year stint as premier before reclaiming the presidency.

ECONOMIC CLOUT

“Winter is coming,” Evgeny Borisovich, a 60-year-old engineer who voted for Sobyanin and declined to give his last name, said outside a polling station. “We need the mayor with the experience to provide water, heating and keep things working, rather than these dilettantes.”

Luzhkov oversaw a construction boom during his 18 years in office, with his billionaire wife, who controlled a building company, becoming Russia’s richest woman. In the last Moscow election in 2003, he defeated newspaper tycoon Alexander Lebedev, who won 13 percent backing.

Moscow, a city of 12 million people, has a $50 billion budget and accounts for about a quarter of Russia’s gross domestic product, official data show. The city plans to sell as much as 160 billion rubles ($4.8 billion) of debt by year-end to trim borrowing costs, according to the Moscow finance department. Its ruble bonds due June 2022 yielded 7.83 percent on Sept. 6, data compiled by Bloomberg show.

Courting Bankers

Navalny, who raised about $3 million for his mayoral campaign, has pledged to reduce corruption, make Moscow’s government more efficient and rein in illegal immigration, a theme Sobyanin has also pursued.

He courted bankers from OAO Sberbank and Deutsche Bank AG at a dinner at Moscow’s Ritz Carlton hotel and last month won the backing of 38 Russian Internet entrepreneurs, who endorsed his candidacy in a manifesto that called for the rule of law to be upheld and government officials held accountable.

Navalny has also sought to challenge Sobyanin’s credibility, asserting in August blog postings that two of the acting mayor’s daughters own apartments worth $3.5 million and $5 million. Sobyanin said the property holdings are legal.

“I voted for Navalny and against Sobyanin,” advertising executive Denis Gerbich, 30, said at a Moscow polling station. “It’s obvious that something needs to change as the authorities have gotten too comfortable with their power.”

OPPOSITION CRACKDOWN

Navalny’s participation in the Moscow ballot had been in doubt after a court in the city of Kirov sentenced him in July to five years in prison for defrauding a state timber company, in a verdict denounced by the U.S. and Europe. He was released a day later pending appeal after thousands protested in Moscow and other major cities. If upheld, the conviction would preclude him from ever holding public office.

Putin dismissed Navalny’s anti-corruption campaign as a way of getting votes, saying his opponent wasn’t “crystal clear” in a Sept. 3 interview with the Associated Press and state-run Channel One.

Putin, 60, has intensified a crackdown on the opposition since winning his latest six-year term, tightening rules for foreign-funded non-government organizations and imprisoning protesters. A top economist, Sergei Guriev and former chess grandmaster Garry Kasparov, critics fearing prosecution, fled Russia this year.

While analysts including Gleb Pavlovsky, head of the Effective Policy Foundation in Moscow, have suggested Sobyanin may become a candidate to replace Putin in 2018 elections, the Moscow mayoral battle may prove to be a launch pad for an assault by Navalny on the higher echelons of power.

‘DISGUSTING, CORRUPT’

“My ambitions are to change my country and I’m ready to take part in presidential elections,” Navalny said in August. He’s vowed in the past to imprison Putin and his billionaire allies if he comes to power, labeling the current political set- up as a “disgusting, corrupt system.”

For now, the very fact he’s able to take on Sobyanin is a sign of political progress, according to Mikhail Vinogradov, head of the St. Petersburg Politics Foundation.

“This is the first competitive federal election since Putin came to power,” he said Sept. 5. “For Navalny, the result isn’t as important as his ability to exit on an emotional high because this clearly won’t be his last or biggest campaign.”