Jailed Kremlin critic Alexei Navalny has vowed to maintain his opposition to the Russian government on the second-year anniversary of his incarceration.
Navalny, 46, was arrested exactly two years ago on Tuesday, returning to Russia from Germany, where he had been treated for poisoning from a deadly Soviet-era nerve agent.
The staunch Kremlin critic -- alongside some western countries -- claim it was a botched assassination attempt by the Russian state. Moscow denies involvement.
"Our miserable, exhausted Motherland needs to be saved," Navalny wrote on Twitter via his lawyers. "It has been pillaged, wounded, dragged into an aggressive war, and turned into a prison run by the most unscrupulous and deceitful scoundrels."
"Any opposition to this gang -- even if only symbolic in my current limited capacity -- is important. I'm not going to surrender my country to them, and I believe that the darkness will eventually fade away."
Friends and allies of Navalny, a lawyer and anti-corruption activist, have campaigned for his release from a high-security prison in Russia.
Last week, his wife last week appealed to prison staff to provide him with basic medicines, with his supporters warning that his life was in urgent danger.
Alexei Melnikov, a member of an official Russian prison monitoring team, visited Navalny and said his health was not in danger, TASS news agency reported on Tuesday.
"We talked with him for more than two hours - I can say that at the moment nothing is threatening his health. Previously, Navalny had symptoms of a cold, but he was treated," the Russian state outlet quoted Melnikov as saying.
Navalny is the highest-profile opposition activist in Russia, still alive. He gained followers with repeated investigations claiming to reveal that the ruling class have enriched themselves lavishly at the expense of ordinary Russians.
The Kremlin was forced to deny in 2021 that Putin owned an opulent palace on the Black Sea, as Navalny alleged in a video with 125 million views on YouTube.
Putin rarely mentions Navalny, and never by name.
The lawyer-turned-activist was sentenced to 11 and half years in jail in two separate fraud cases.
Amnesty International described the trial as a "sham", while Navalny himself said the charges were trumped up to silence him. His anti-corruption organisation has been banned as extremist.
Dasha Navalnaya, his daughter, appeared in a video clip on Tuesday, launching a campaign to free her father.
She said the 46-year-old was being repeatedly and unjustly put in solitary confinement in prison for his fierce opposition to Russia's war in Ukraine.
"Of course the real reason my dad is in a punishment cell are his anti-war statements. And now they're tormenting him and depriving him of any connection with the outside world in order to silence him," said Navalnaya.
"But my father is not afraid and will not stop fighting. My dad is an innocent man and deserves to be free."
Russia's federal prison service, FSIN, has defended Navalny's conditions in the past, while the authorities say his incarceration is legally sound.