By RICHARD BOUDREAUX and ALEXANDER KOLYANDR

MOSCOW—Muscovites wearing white ribbons ventured out under a light snow Sunday and created a festive spectacle like nothing anyone remembers seeing before in the Russian capital. They formed a human chain along the entire 10-mile Garden Ring Road encircling the city center.

For an hour they stood side by side, joined hands, chatted and waved at passing motorists who honked in approval. In case no one got the point, a few held signs alluding to their purpose—the end of autocratic rule by the man expected to win next Sunday’s presidential election, Vladimir Putin.

In Moscow, people came out by the thousands to form a human chain in protest of prime minister and presidential candidate Vladimir Putin. Video and reporting by WSJ’s Alexander Kolyandr. (Photo: AP)

The chain of an estimated 35,000 people recruited and organized over the Internet was the fourth large anti-Kremlin action in 11 weeks, evidence that middle-class Muscovites are ready to invent new forms of street protest against corruption and rigged elections. Another mass demonstration is planned for the day after the vote.

But it is also clear that such periodic peaceful actions alone won’t bring down Mr. Putin, who all but ignores them, and that protest leaders lack a clear strategy to ramp up the pressure. The standoff could produce months or years of conflict after Mr. Putin, now prime minister, makes his anticipated return to the presidency for a third term.

“People’s fatigue is obviously one of the risks,” said Boris Nemtsov, an organizer of the white-ribbon movement, adding that Mr. Putin enjoys strong support in smaller cities across Russia and “will not let go of power easily.”

“This is not a sprint,” he said. “It’s going to be a marathon.”

ReutersSome of the opposition supporters who formed a human chain along Moscow’s Garden Ring Road on Sunday to protest Vladimir Putin’s likely return as president.

The Kremlin has rejected those demands. Protest organizers have countered with an “anyone-but-Putin” campaign for Sunday’s election, even though they don’t feel represented by any of his four Kremlin-connected challengers. With genuine opposition parties excluded from the ballot by bureaucratic hurdles, the protest leaders are preparing to dispute a Putin victory as well with rallies throughout the spring and summer.

Their movement, however, has neither a nationally recognized leader nor a national reach. Recent anti-Kremlin rallies in St. Petersburg and other cities have drawn no more than a few thousand each. Some protest leaders talk of calling a national strike in the coming months; others say there is no sign that blue-collar workers across the country, many belonging to unions loyal to Mr. Putin, would join in.

“They have high moral standing but no political bargaining power,” said Masha Lipman, a political analyst at the Carnegie Moscow Center who sympathizes with the protesters. “When they say, ‘If you don’t meet our demands, we’ll occupy the streets again,’ that doesn’t sound like a strong ultimatum.”

Eduard Limonov, a veteran nationalist opposition leader, told Interfax news service that Sunday’s action “belongs in the category of entertainment. It will have no effect on those in power.”

In the run-up to Sunday’s vote, Mr. Putin’s numbers in polls generally believed to be reliable have recovered from a dip after the first protests to nearly 60%. Analysts attribute the rebound to a strong TV campaign portraying him as a guarantor of stability, a quality attractive to the two-thirds of voters who live outside big cities and whose incomes depend largely on the state.

“This mass will obediently go out and vote [for Putin] despite their dissatisfaction because inertia is strong, as is the fear of change,” said Lev Gudkov, head of the Levada Center, an independent polling agency.

That outlook failed to damp the spirit of those joining hands Sunday for what they called “the great white ring.” They came with their children and white-beribboned dogs and cats. Many wore white hats, scarves, gloves and parkas, and carried white balloons and carnations.

Standing on sidewalks outside banks, supermarkets and apartment blocks, the buoyant crowd covered nearly every stretch of the circular highway between intersections, including its two bridges over the Moscow River. A group of army paratroop veterans stood in the crowd with their units’ banners near Gorky Park.

Sunday was the last day of Maslenitsa, a weeklong Eastern Orthodox religious and folk holiday when Russians celebrate the imminent end of winter. One protester held up a portrait of Mr. Putin and the words: “Putin, go away with the winter.”

“I hope I will be able to go to protests until this regime is changed,” said Irina Antonova, a middle-aged woman in the chain near Tchaikovsky Hall. “The government is not ready to hear the people, but I hope there will be ways to change it over time.”

She added, however, that as long as high prices boost Russia’s oil-export income, “I’m afraid Putin will cling to power.”

A 38-year-old protester who gave his name only as Roman said he came out to get back at the Kremlin for obliging his wife, who works at the state-controlled oil company Rosneft, to attend a pro-Putin rally last week.

Police and riot troops stood vigil on the highway Sunday but didn’t interfere. Nor did they move against the roughly 1,000 protesters who left the Ring Road action and marched in a circle in Revolution Square, near the Kremlin, chanting against Mr. Putin.

Unlike previous protests since December, neither the Ring Road chain nor the march had official permission. The police restraint appeared to be part of a Kremlin strategy of permitting and minimizing the protests—one that isn’t certain to last.

Russia’s state TV channel aired a brief report on the chain protest but gave equal time to a much smaller number of pro-Kremlin demonstrators who walked along the Ring Road with heart-shaped signs saying “Putin Loves Everyone.”

—Gregory L. White and Ira Iosebashvili contributed to this article.Write to Richard Boudreaux at richard.boudreaux@wsj.com and Alexander Kolyandr at Alexander.Kolyandr@dowjones.com