A casual observer on Moscow’s Pushkin Square on Saturday could have been forgiven for mistaking the scene for events that have wracked neighbouring Belarus for the past five months.

One protester held up a white-and-red flag, the symbol of the protests against Belarusian strongman Alexander Lukashenko. Others chanted “Long live Belarus!” as cars honked in support and blared “Changes”, a Soviet dissident rock anthem adopted by protesters there. Baton-wielding riot police in balaclavas and body armour beat people in videos that circulated widely on Twitter and Telegram.

If the rally — which attracted an estimated 40,000 people in Moscow and thousands more in 110 other cities nationwide — had more than a whiff of Minsk to it, the sudden outburst of anti-government sentiment only a short walk from the Kremlin has put Russia in a similar bind to Mr Lukashenko.

As protests surged, Mr Lukashenko asked Russia to send riot police, warning “if Belarus falls, Russia will be next”. Wary of antagonising Belarusians against Moscow, Vladimir Putin, Russia’s president, declined the request.

But after the arrest of opposition activist Alexei Navalny prompted Saturday’s protests — the largest anti-Putin rallies in years — the Kremlin’s own heavy-handed crackdown risks misjudging public sentiment and legitimising a national movement against it much as Mr Lukashenko’s did, analysts say.

Police detained 3,345 people on Saturday, according to independent monitor OVD-Info, which said the arrests were a record in its decade of tracking them.

Saturday’s protests were also the first under Mr Putin’s rule where Russians fought to break through barricades, free detainees from custody, or threw snowballs to drive back police, which state media claimed led to about 40 officers sustaining injuries.

“Nobody thought this could happen before, just like in Belarus,” said Andrei Kolesnikov, a senior fellow at the Carnegie Moscow Center. “But the rise in protest activity shows you that a huge number of people are unhappy with the government . . . People aren’t coming out for Navalny so much as they are because they’re tired of corruption and bad governance.”

Mr Navalny, a 44-year-old anti-corruption activist, was jailed this week upon returning from Germany where he had been recovering from a nerve agent poisoning he said was ordered by the Kremlin. He now faces up to 13 and a half years in prison on two separate charges he claims are retribution for his activism.

The day after his arrest, Mr Navalny released a two-hour video investigation claiming oligarchs had spent billions on a lavish palace for Mr Putin on the Black Sea coast. The video racked up 78m views on YouTube by Sunday and clearly inspired some of the protesters.

Some waved toilet brushes in reference to expensive home goods allegedly procured for the palace, while others chanted “Aqua disco!” in reference to a fountain outlined in the floor plans Mr Navalny published.

Despite threats of reprisals from security forces, Mr Navalny’s supporters are calling for new rallies next weekend in the hope they can seize the initiative.

“We know what we need to do, we know what we want, and we believe that we can get him out,” said Leonid Volkov, who runs Mr Navalny’s regional network from self-exile in Vilnius.

“Obviously, Alexei’s return has forced Putin into a very unpleasant choice. Either he arrests him, which is a bad option, or he doesn’t, which is just as bad an option.”

The Kremlin denies any involvement in Mr Navalny’s poisoning and says Mr Putin has no connection to the palace. It has also sought to play down the protests as the work of an aggrieved minority. “Many are going to say that lots of people came to the illegal protests. No, only a few came out, but lots of people vote for Putin,” Kremlin press secretary Dmitry Peskov said in a state TV interview on Sunday.

Anecdotal data from Saturday’s protests, however, suggests the dynamic may be changing. According to Alexei Zakharov, who led volunteers from a monitoring group in conducting 359 interviews in Moscow, 42 per cent of those who attended had never attended a protest before, while nearly half of them were women.

“One issue in common [with Belarus] is you’re seeing young people out there on the streets and that is lending a surge of energy and enthusiasm,” said Philip Worman, managing director of GPW, a political risk firm. “You have young people who don’t care any more, and that is slowly eroding away the collective national willingness for status quo, nostalgia and stability.”

Mr Navalny’s allies hope the public show of support will convince the Kremlin to release him. In 2013, Mr Navalny was sentenced to five and a half years on fraud charges, but an impromptu rally of up to 7,000 outside the Kremlin prompted a higher court to suspend his sentence the next day.

More recently, unauthorised protests in Moscow in 2019 helped secure a rare about-face for Ivan Golunov, an investigative journalist arrested on drug charges the police later admitted were fabricated.

The Kremlin, however, appears more resolved this time to remove Mr Navalny from the political playing field. State television said protesters had committed “atrocities” against police and claimed they were using “Maidan technologies” developed by US intelligence during protests in former Soviet states.

That mirrors claims by Mr Lukashenko, who has accused foreign powers of using Belarusian protesters as “cannon fodder” against his regime.

“Given the example of the political techniques tested in Belarus and Kyrgyzstan, we cannot rule out the possibility of similar destabilisation in our country,” Russia’s first deputy interior minster Alexander Gorovoi said on Thursday, ahead of the protests.

Mr Kolesnikov, however, said the Kremlin’s mistake was to “underestimate Navalny’s level of support”.

“When people saw what was happening to Mr Navalny live on TV, and then the film [about the palace], it provided a strong emotional impulse for them to take to the streets,” he added.