Putin saw his ratings plunge to historic lows last year as grievances built up among the public over the declining personal incomes, diminishing personal freedoms, and the government's handling of the coronavirus pandemic.
A day after Navalny's arrest, his team poured fuel over the growing dissatisfaction by releasing a bombshell two-hour long documentary into a lavish property at the Black Sea they estimate to cost around $1.4 billion, which they allege was created for Putin.
Putin, who once scored points among voters with populist statements about the Russian government's battle against widespread corruption, denied having any links to the palace, but the film seemed to have struck a nerve with the Kremlin.
In the days leading up to the protests, Mash, a channel on the encrypted messaging app Telegram with links to a pro-government media holding, posted an interview with Putin's close childhood friend Arkady Rotenberg, a billionaire mostly inaccessible to journalists. Rotenberg claimed he owned the property and announced he was building a hotel there.
"Our entire investigation is about Putin using his best friends to hide his assets. In response, the Kremlin shows Rotenberg and declares him the owner of the palace," Maria Pevchikh, one of the investigation's authors, said in a tweet. "They think that they are saving the situation, but in fact they are doing the exact opposite."
Many protesters CNN spoke to during this and last weekend's protests said they were already disenchanted with the government, but Navalny's detention and his investigation into Putin pushed them to take to the streets.
Some said they never protested before out of fear of repercussions.
"It all influenced me to come here today because I saw that they violated the law right in front of everyone," Mikhail, 27, told CNN on Sunday near one of the subway stops where police were detaining people en masse.
Police detentions in Moscow
The Kremlin's preparations for the weekend protest were not limited to barricades and cordons. Navalny's key allies were all detained more than 10 days ago in an apparent effort to stifle the unrest. Many, including Navalny's brother Oleg, have been under house arrest for the past two months.
Last week, however, the circle of wanted activists expanded widely.
Among the most shocking cases was that of Anna Vellikok. She was held for 14 days after her arrest for retweeting her boyfriend, Anti-Corruption Foundation investigator Georgy Alburov, one of the filmmakers of the documentary that investigated the Black Sea property.
According to materials in the case that Vellikok posted, Vellikok was detained and subsequently arrested for retweeting Alburov's post that linked to a YouTube video where Navalny urged people to protest from inside a court hearing.
The judge ruled that by retweeting it, she instigated unsanctioned rallies.
"Of course, they are giving me 14 days not for tweets and retweets, but for the fact that the video about Putin's palace has become so popular. Because so many people took to the streets. Because I'm dating (Georgy)," she tweeted from the court room on Saturday.
Sergey Smirnov, the editor-in-chief of an independent outlet called Mediazona, was detained on Saturday while taking a walk with his young son, according to a video posted on his Twitter.
He was charged with allegedly inciting rallies on January 23 and later released, on the condition he show up for a court hearing next week after being. Smirnov has said he was at home on the 23rd.
These nighttime raids and arrests of Navalny supporters have fed fears of worsening political repressions in Russia, protesters said.
"The fact that Anna Vellikok is now being tormented the same way as Oleg Navalny was has been driving me crazy," Inga Kudracheva, an HR manager based in Moscow, said in a viral tweet.
"They are just family members of those who dared to jump at Putin personally and talk about his palace built on bribes. How is this not 1937?" she added in a reference to the height of purges led by Joseph Stalin.
Other governments respond
The widespread detentions also drew condemnation from the US -- including Rebecca Ross, the spokeswoman for the US Embassy in Moscow, and newly minted US Secretary of State Antony Blinken.
On Sunday, Blinken condemned the "persistent use of harsh tactics against peaceful protesters and journalists by Russian authorities for a second week straight."
"We renew our call for Russia to release those detained for exercising their human rights," he continued, referring to Navalny.
The Russian Foreign Ministry in turn accused the US of "gross interference" in the internal matters of Russia, saying Blinken was supporting the "violation of law" in a statement posted on its official Facebook page.
The FBK has urged US President Joe Biden
to impose sanctions on at least eight high-profile Russian figures it says are close to Putin.
FBK executive director Vladimir Ashurkov, who signed the letter, told CNN on Saturday that the foundation was calling on the United States to put pressure on Putin to release Navalny.
But journalist and campaigner Zhanna Nemtsova, the daughter of murdered Russian opposition politician Boris Nemtsov, said Sunday she believed Kremlin critic Alexey Navalny "will be locked away in prison for many years."
"The only way to support Alexey Navalny is to take to the streets," Nemtsova, who has joined the protests in Moscow, told BBC radio. "We have no choice, and it is what can partially guarantee Navalny's security while he's in prison," she said.

Nemtsova's father, former deputy prime minister Boris Nemtsov, was assassinated on a Moscow bridge within sight of the Kremlin in 2015. Nemtsov was then considered the most visible leader of the Russian opposition. Five Chechen men were handed prison sentences for his killing in 2017.
"Lots of people have nothing to lose, especially young people," Nemtsov told the program when asked about the hopes of the thousands of people who have been protesting across Russia since Navalny's arrest.
"We are experiencing another economic downturn. In many cases, if you want to pursue a decent career, you have to be loyal to the government. Of course, it is very depressing for many people," she added.
Navalny's team said on social media they view the Sunday demonstrations as "a success" and announced that the "next stop" for demonstrations will be on Tuesday at Navalny's court hearing.
"Today's protest is over, but we continue to fight for Alexey Navalny's freedom," the team posted on Telegram Sunday evening.
CNN's Zahra Ullah, Mary Ilyushina, and Anna Chernova reported from Moscow, and Laura Smith-Spark wrote from London. CNN's Frederik Pleitgen, Martin Goillandeau, and Ali Main contributed to this report.
Source: CNN International