A day after Russia’s largest wave of unsanctioned protests in years, opposition leaders on Monday cheered the turnout as a sign of widespread dissatisfaction with the system created by President Vladi­mir Putin.

Anti-corruption whistleblower Alexei Navalny has sent the Kremlin a sharp message by single-handedly sparking nationwide rallies noteworthy both for their geographic diversity and the enormous tally of protesters detained in a single day.

The question now is how authorities will respond to the show of defiance.

In Moscow, Navalny was ordered jailed for 15 days and fined $350 on two charges, including refusing to obey police. That will give the Kremlin time to review what happened and decide whether to ignore the protests, accede to demonstrators’ demands to crack down on official corruption, or launch a crackdown of their own on opposition leaders.

[Here’s what I saw at the huge Moscow anti-corruption protest]

1 of 29 Full Screen Autoplay Close Skip Ad × See photos of Russian citizens protesting against government corruption View Photos Unsanctioned rallies swept across Russia to protest corruption in the government of President Vladi­mir Putin. Police respond with barricades, tear gas and hundreds of arrests. Caption Unsanctioned rallies sweep across Russia to protest corruption in the government of President Vladimir Putin. Police respond with barricades, tear gas and hundreds of arrests. Moscow Riot police stand guard blocking a street during an anti-corruption rally in central Moscow called by prominent Kremlin critic Alexei Navalny, who was arrested along with scores of others. Alexander Utkin/AFP/Getty Images Buy Photo Wait 1 second to continue.

The high number of arrests — more than 1,000 people were taken into custody in Moscow alone, and dozens more in cities across the country — provided a sign that authorities were ready to respond in force if protesters try again.

Navalny had called for the rallies after he published a report alleging that Russia’s prime minister, Dmitry Medvedev, has amassed a fortune in luxury yachts, estates and vineyards. He said the size and scope of the protests indicated that Russians were fed up with Putin’s government, despite an approval rating that has not dipped below 80 percent in three years.

“Yesterday’s rallies, especially the number of them in outlying regions — we haven’t seen anything like that since the 1980s — first of all shows how completely artificial that famous 84 percent support is,” Navalny told The Washington Post via Facebook Messenger in the courtroom.

Putin spokesman Dmitry Peskov, responding to the protests for the first time Monday, brushed aside the notion that they were a sign of anything significant, and instead called them a “provocation” because organizers lied when they told people the demonstrations were legal. “We cannot respect those who mislead people by calling for illegal rallies,” Peskov added.

Peskov pointed out that authorities had offered a park northeast of central Moscow for the demonstration. Throughout Sunday’s rally, police urged protesters to go there.

Peskov also claimed that teenagers — who showed up in large numbers — were paid to turn out.

As has become his practice, Peskov avoided mentioning Navalny by name. Actually, demonstrators on Sunday did, too: No one was chanting Navalny’s name at the Moscow rally. Among the chants were, “We want answers,” “You can’t jail everyone,” and “Shame.”

(David Filipov, The Washington Post)

Official Moscow has dismissed Navalny, who has said he will run for president in 2018, as a widely reviled nuisance with little political support and whose allegations of official corruption are an attention-grabbing stunt. Furthermore, a conviction in a fraud case, which Navalny says was politically motivated, could block him from entering the race.

Putin, who almost certainly will run for reelection or anoint his successor, is hoping for a landslide to validate his past six years of authoritarian rule. State-run television, where most Russians get their news, ignored the rallies, including the demonstration in Moscow, where by some estimates 25,000 people showed up.

[How to understand Putin’s jaw-droppingly high approval ratings]

Authorities had sought to keep people from turning out by refusing to grant permits to organizers in dozens of cities and warning of arrests if the demonstrations were held without permission.

Instead, the rallies appeared to amount to the largest coordinated protests in Russia since the street demonstrations that broke out in 2011 and 2012 after a parliamentary election that opposition leaders decried as fraudulent. Back then, Putin accused Hillary Clinton, secretary of state at the time, of inciting the protests.

On Sunday night, the State Department condemned the detentions, and called for the release of peaceful protesters.

Peskov said the Kremlin “cannot agree” with the American appeal. The detained protesters, he said, had broken the law by attending demonstrations that had not received permits.

The challenge confronting Russia’s small, fractured opposition is to find a way to take advantage of the popular discontent.

Vladi­mir Milov, the leader of Democratic Choice, one of a handful of small opposition parties, suggested that Russia under Putin has reached a turning point.

“The entire country is against Putin; no one turned out to support Putin,” Milov wrote in his party’s Livejournal blog. “We say that the only thing propping up this regime is law enforcement and brutality, but even here there are signs of cracking.”

Sergei Markov, a pro-Kremlin analyst, agreed that Navalny had scored a “serious success” by pulling off rallies in dozens of cities “despite the bans and arrests.” He also noted that many participants were younger than the people who usually show up at demonstrations.

“The new phase of the radical opposition is clearly not aiming at elections, where pensioners vote, but on mass disorder in the streets, where young men of draft age take part,” he said.

But Navalny said the rallies suggested strong support for his anti-corruption platform in an election campaign.

“If thousands of people turn out for unsanctioned meetings in the regions, that means millions support them,” Navalny said. “This confirms that people will come out to elect a person with my views. Now our demand to allow me to run looks even more authoritative.”

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