Anti-government protests took a sharp turn Saturday, as younger faces took the stage with a new message and thousands rallied to show they have the stomach for a long fight ahead.

The message was less rousing and more practical than in earlier demonstrations. With fewer chants of “Russia without Putin” and more calls for individual action, protest leaders began pointing toward the direction ahead and reflecting on the difficulty of change as they seek new leaders and to build institutions.

Their challenge is clear: Last Sunday, Vladimir Putin won a six-year term as president with nearly 64 percent of the vote. Critics attributed that as much to efforts to prevent competitive candidates from running for office as to voting irregularities. The protesters know they first have to force their authoritarian system to allow fair competition in elections. Only then can they get choice on the ballot.

“Beginning Monday, no matter what, let’s start building a civil society,” said Vadim Korovin, who was arrested Feb. 29 as he took tents out of his car to give to would-be protesters. “Like you, I don’t know how we’ll do it, but we need a society that’s free and fair.”

Maxim Katz was elected as an independent last Sunday, along with a few dozen other young Muscovites, to neighborhood groups that offer advice to the city council and that have been dominated by Putin’s ruling United Russia party. Everyone had told him it was ridiculous to consider a run for office, even a minor one, he said. Now he has taken a first step into politics, however small.

“All of our lives people have been telling us it’s useless, useless, useless,” said Katz, long-haired and 27. “The fix is in. Parents, friends, grandmothers, grandfathers — all told us that. But just go and do what you believe should be done. You will succeed.”

The crowd shouted approvingly: “Katz for president!”

Police estimated the gathering at 10,000, but organizers put it at 25,000, still far less than the heady demonstrations of December, when 100,000 or more roared their disdain for Putin. People came and went in freezing but brilliant afternoon sunshine, making precise counts elusive. The numbers were large considering that many Muscovites had decamped for a long holiday weekend, which began Thursday on International Women’s Day. Wednesday night, the roads out of town were at a standstill.

Maybe the crowd was smaller, said Sergei Parkhomenko, a journalist and protest organizer, but just three months ago protest was unimaginable and politics repellent to most.

“We have new people on this stage,” he said, “people we’ve never heard from before. There are many of us, and we’ve learned a lot these last three months.”

Election observers were the day’s official heroes, applauded for being on the front lines of the fight to build civil society.

Konstantin Maslov said election work provided an opportunity to come together at the district level, with friends, family and neighbors. “Let’s build this from the ground up,” he said.

The crowd started to jeer Ksenia Sobchak, a socialite whose late father was mayor of St. Petersburg and Putin’s mentor. But she plowed on, talking about her work as an observer, insisting that it was time for everyone to join together. When she finished, applause drowned out any disapproval.

More than 2,000 police lined Novy Arbat, the broad avenue normally filled with official cars pushing ordinary motorists aside. Two helicopters buzzed overhead, but the crowd paid them little attention. As the temperature rose to the high 20s, seeming almost springlike for Moscow, spirits warmed — in marked contrast to the glumness Monday, at a rally to protest the election of Putin.

The protesters are an unlikely coalition of liberals, Communists, nationalists and radicals. But liberals are tiring of what they consider nationalist rants. Radicals want more confrontation than others support. Several protesters said each group needs to find leaders who will speak to them, while maintaining a solid front for change.

The movement will have to split apart into logical constituencies, Ilya Ponomaryov, a social democrat member of parliament and protest leader, said in an earlier interview. But it also needs to find a unifying candidate for presidential elections.

“We have to create an alternative to Putin,” he said. “But the problem is media access.”

The differing approaches were soon evident Saturday.

Sergei Udaltsov, leader of the socialist Left Front who said he wants to plan a million-person march before Putin’s May 7 inauguration, led a line of his supporters away from the rally toward Pushkin Square. Udaltsov, who was arrested after Monday’s protest, was detained Saturday for organizing a provocation and later released with a court date. About 50 nationalists were arrested as they marched along the nearby Stary Arbat.

In St. Petersburg, police detained about 60 people for trying to gather without a permit, and about 50 people were detained in Nizhny Novgorod on the same grounds.

“Everyone here is very different,” said Yevgeny Kagan, 53. “I don’t have much in common with the Communist or leftist parties. What’s worse, we don’t have the possibility of normal elections.”

The people who could speak for him, he said, have not been allowed on the ballot.

“What we need is our right for normal elections,” he said, “and if I knew how to accomplish that, I’d be up on stage with them.”