Alexei Navalny is seen in 2012 behind the bars in a police van after he was detained during protests in Moscow a day after Vladimir Putin's inauguration.

Caption

Alexei Navalny is seen in 2012 behind the bars in a police van after he was detained during protests in Moscow a day after Vladimir Putin's inauguration. / AP

MOSCOW — Alexei Navalny, Russia's most prominent political opposition figure, has died in a remote Russian prison at age 47.

News of Navalny's death came Friday from the Federal Penitentiary Service in the Yamalo-Nenets Autonomous District, above the Arctic Circle.

In a statement, prison authorities said Navalny "felt unwell" after a walk in the prison yard and soon lost consciousness. Attempts by emergency medics to resuscitate him "failed to give positive results."

Navalny had been serving out a lengthy prison sentence for charges including extremism, which were widely seen as punishment for his years of criticism of Russian President Vladimir Putin.

Kremlin spokesperson Dmitry Peskov said Putin has been informed of Navalny's death. He said prison medics are working to identify the cause of death.

Reactions swiftly poured in from around the world. U.S. Secretary of State Antony Blinken said Navalny's "death in a Russian prison and the fixation and fear of one man only underscores the weakness and rot at the heart of the system that Putin has built. Russia is responsible for this."

Concerns over Navalny's well-being and safety while in prison were long-standing.

His family members and supporters say authorities repeatedly denied Navalny medical care and subjected him to long, punishing stints in solitary confinement with the apparent aim of preventing his access to the outside world. A representative of his Anti-Corruption Foundation in Washington, D.C., expressed the belief in April that Navalny was slowly being poisoned in prison.

Yet a video shared by Russia's independent SOTA news service appeared to show Navalny looking healthy and in good spirits during a court hearing the day before his death. Navalny was participating by video feed.

Navalny had been serving out a 19-year prison sentence on charges including extremism, embezzlement and fraud — widely seen as Kremlin retribution for his political activities.

A vehement critic of President Putin for more than a decade, Navalny built a national following with campaigns that channeled public outrage over corruption at the highest level of government — and promoted a vision that Russians could, one day, live differently.

Even from his prison cell, he was a critic of Russia's invasion of Ukraine and Putin's increasingly repressive rule.

Indeed, in the days before his disappearance in December, the opposition figure unveiled a campaign to rally Russians against Putin when he runs for a fifth term as president in elections scheduled for March.

A new voice of opposition

Navalny was born on June 4, 1976, in a village outside Moscow.

A lawyer by training, he first rose to prominence with efforts to foment shareholder revolts at Russia's corruption-ridden state companies.

He later emerged as the breakout political star of anti-government protests — a powerful speaker who railed against flawed parliamentary elections in 2011 by memorably labeling the Kremlin's ruling United Russia bloc "the party of crooks and thieves."

A crackdown on protesters that followed signaled Putin's determination to keep his grip on Russian political life — even as the Kremlin continued to manage degrees of political competition.

Navalny was allowed to run for mayor of Moscow in 2013 despite fighting off an embezzlement conviction widely seen as a Kremlin attempt to undercut his appeal with voters. He nonetheless placed second — nearly forcing the race to a runoff with the Kremlin's hand-picked candidate — thanks to a spirited street campaign.

The Kremlin took fewer chances when Navalny tried to challenge Putin for the presidency in 2018. A court ruled him ineligible, but Navalny forged ahead with a shadow campaign that saw him open offices nationwide and lay out his political vision.

"I want to live in a normal country and refuse to accept any talk about Russia being doomed to being a bad, poor or servile country," Navalny told NPR in an interview at the time.

"I want to live here, and I can't tolerate the injustice that for many people has become routine."

A contrast to Putin

Even from the political sidelines, Navalny's informal style — honed by an internet-fueled sense of humor — contrasted starkly with the imperious bearing of Putin.

Navalny was known to inject quotes from favorite shows — like animation series Rick and Morty or HBO's The Wire — into his speeches.

"Hey, it's Navalny!" was his standard greeting in videos before he would tear into Putin.

It was a hint at what made the two men so different — and Navalny, his supporters argued, a threat. Even if Navalny wasn't allowed to compete in elections.

Russian opposition leader Alexei Navalny sits handcuffed in court in Moscow on March 30, 2017.

Caption

Russian opposition leader Alexei Navalny sits handcuffed in court in Moscow on March 30, 2017. / AP

Putin tapped into older Russians' grievances over the end of the Soviet Union. Navalny channeled a younger generation's hope that Russia could break free from its repressive Soviet past.

Putin, famously, sought to downplay Navalny's fame by refusing to even utter his name in public — a position Navalny mocked with characteristic humor for an Instagram bio: "Aforementioned person, Other politician, Various activist, This gentleman, Characters that were mentioned."

The phrases were all Putin word salads to avoid pronouncing Navalny's name directly.

Yet Navalny had detractors beyond the Kremlin. He repeatedly took part in Russian nationalist movements early in his political career, arguing their support was necessary if the opposition hoped to win.

Some Russian liberals never forgave him. State media labeled him a "fascist."

Harnessing social media

Banned from national television in Russia, Navalny mastered the use of social media — in particular, YouTube — to promote his political message.

In 2011, Navalny launched the Anti-Corruption Foundation, assembling a team of talented Russians who used public records — and occasionally the dark web — to investigate evidence of graft among Russia's most powerful.

Navalny led investigations excoriating ministers for displays of extravagant wealth far beyond their declared incomes and, in one instance, use of government planes to ferry pet corgis to dog competitions.

His most popular video was a two-hour film in 2021 that took viewers inside a secret palace on the Black Sea that Navalny claimed had been built by Putin for more than $1 billion.

As the audience for the film grew to over 100 million views, a Kremlin-affiliated oligarch stepped forward to say he had bought the property as an investment.

Navalny's audience was growing. But so, too, were his enemies among the Russian elite.

Threats and Novichok

Over the years, Navalny led repeated nationwide protests against Putin and Kremlin cronyism. He and his supporters were arrested dozens of times; in 2011 alone, he was detained 15 times.

But with his growing popularity — particularly among younger Russians — came growing threats to Navalny's safety.

In May 2017, an attacker doused him with a chemical agent that nearly left him blind in one eye.

Then, in August 2020, Navalny collapsed on a flight from Siberia to Moscow. He was later medevaced while in a coma for treatment in Germany — where doctors found traces of the Soviet-era nerve agent Novichok in his blood.

As he recovered over several months, Navalny worked with journalists to investigate the attack — delivering another sensation.

Navalny tricked one of the would-be assassins into confessing he'd been instructed as part of a team from Russia's security service to smear the poison on Navalny's underwear.

Navalny alleged it could only have happened on the orders of President Putin.

The Kremlin dismissed the charge outright, insisting improbably that the attack had been staged.

Meanwhile, the government renewed an old fraud conviction against Navalny, alleging he had violated his parole as he recuperated in a hospital abroad.

The move appeared intended to force Navalny to remain in exile. Navalny insisted on returning to Russia anyway.

Critic to the end

May 8, 2012: Alexei Navalny (center), a prominent Russian anti-corruption whistleblower and blogger, speaks to protesters gathered across the street from the presidential administrations building as a police officer tries to stop him in downtown Moscow.

Caption

May 8, 2012: Alexei Navalny (center), a prominent Russian anti-corruption whistleblower and blogger, speaks to protesters gathered across the street from the presidential administrations building as a police officer tries to stop him in downtown Moscow. / AP

Navalny was immediately detained upon his arrival back to Russia in January 2021 — prompting another wave of protests across the country.

He was quickly sentenced to 2 1/2 years for parole violations in a trial during which Navalny memorably labeled Putin "Vladimir the Poisoner of Underpants" and said his incarceration was intended to intimidate the public.

"You can't lock up millions and hundreds of thousands of people. I hope very much that people will increasingly realize this," Navalny said in the trial.

"And once they do — and such a moment will come — this whole thing will fall to pieces because you can't lock up the whole country."

Another trial on fraud in 2022 added a concurrent sentence of nine years.

Meanwhile, authorities moved to dismantle Navalny's political network, labeling the Anti-Corruption Foundation and its members "extremist." Several associates were arrested. The rest went into hiding or fled abroad.

Yet even from behind bars, Navalny remained a political presence.

Internationally, attention to his plight continued to grow: He was awarded a top European human rights prize in 2021, and this year a documentary about him called Navalny won an Oscar.

As Russia launched its attack on Ukraine in February 2022, Navalny repeatedly castigated Putin as a madman waging a "stupid war" that he would ultimately lose.

"Our miserable, exhausted Motherland needs to be saved. It has been pillaged, wounded, dragged into an aggressive war, and turned into a prison run by the most unscrupulous and deceitful scoundrels," Navalny wrote in a social media post in January, marking his second anniversary in jail.

He urged his supporters to campaign against the invasion despite the risk of arrest, maintaining his belief everything could change if more Russians were willing to raise their voices in dissent.

It was one of the latest reminders of Navalny's vision for his country — at once simple and yet stubbornly out of reach in an era characterized by repression and fear.

Navalny called it "the happy Russia of the future."

Navalny is survived by his wife, Yulia Navalnaya, brother Oleg, daughter Daria, and son Zakhar.

NPR's Jaclyn Diaz and Eric McDaniel contributed to this report.