Alexei Navalny, Russian President Vladimir Putin's most prominent critic, said Wednesday he is going on hunger strike in prison in the latest chapter of his high-profile confrontation with the Kremlin.
Over the past decade, the 44-year-old anti-corruption campaigner has emerged as Russia's most prominent opposition politician, even though he has never held elected office.
In February, Navalny was sentenced to two-and-a-half years in prison on old embezzlement charges, becoming the country's highest-profile prisoner who keeps needling the Kremlin from behind bars.
He complained this month that he was losing sensation in both legs due to what he believed was a pinched nerve in his back and said that a prison doctor had not given him a diagnosis.
On Wednesday evening, he announced he is going on hunger strike until he receives proper treatment.
Last August, the father-of-two barely survived a poisoning attack with what Western doctors and experts say was Novichok, a Soviet-designed nerve agent.
The poisoning ordeal has drawn global attention to Navalny and raised his international profile, with German Chancellor Angela Merkel visiting him while he was undergoing treatment in a Berlin hospital.
Navalny's decision to return to Russia in January despite the threat of arrest and jail has been seen as a direct challenge to Putin.
His call for demonstrations was answered by tens of thousands who rallied in cities across Russia in January and February, demanding Navalny's release from prison and denouncing Putin's rule.
- Young fan base -
Navalny has won a young fan base through viral videos exposing corruption among the elites and has 2.6 million followers on Twitter.
He has also grabbed attention with his uncompromising rhetoric and coined phrases such as the "party of crooks and thieves" to slam the ruling United Russia party.
In 2011-2012, Navalny led anti-Putin protests that attracted tens of thousands and were sparked by widespread claims of vote-rigging in parliamentary elections.
In 2013, he stood for Moscow mayor, coming second against Putin ally Sergei Sobyanin.
In 2017, Navalny accused then-prime minister Dmitry Medvedev of massive corruption in a YouTube documentary, sparking a new wave of nationwide demonstrations that were met with police violence and large-scale arrests.
The same year he had to travel to Spain for surgery after one of several street attacks left him nearly blind in one eye.
Navalny has faced a series of legal cases which supporters see as punishment for his activism.
In 2014, he was given the suspended sentence for embezzlement, and his brother Oleg, a co-defendant, was jailed for three-and-a-half years in a decision activists likened to a "hostage-taking".
Before he flew back from Germany in January, papers were filed with a Moscow court asking for that suspended sentence to be converted into jail time, a move Navalny's allies said was an attempt to block his return.
With the Kremlin tightly controlling the media, Navalny nonetheless remains a fringe figure for many Russians, who are exposed to the official portrayal of him as a Western stooge and convicted criminal.
Putin has refused to pronounce Navalny's name in public.
While barred from mainstream politics, Navalny has sought to expose the wealth of Russia's elites, broadcasting investigations to millions of Russians on social media and YouTube.
- Latest expose -
In his latest expose -- released after his January arrest -- he claimed a lavish Black Sea property worth $1.35 billion was built for Putin through a massive corruption scheme.
The report has been viewed more than 115 million times on YouTube and was seen as a driving force behind the latest demonstrations.
But despite tapping into discontent among a largely young urban middle class he is still far from a unifying opposition figure, and some have criticised his anti-immigrant nationalist stance.
He scored political success in local elections in 2019 and 2020, when pro-Putin parties suffered losses because of a "Smart Voting" plan Navalny put forward after his allies were barred from standing in numerous races.
The tactic calls for voters to support the one candidate most likely to defeat the ruling party and saw Kremlin-linked candidates drop seats in the Moscow assembly in 2019.
Navalny's offices have been raided repeatedly since, while his Anti-Corruption Foundation was declared a "foreign agent" and ordered to pay several large fines.