'I'm not going to surrender': Jailed Kremlin critic Alexei Navalny vows to keep opposing Moscow

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