Alexei Navalny says he's going on a hunger strike while detained in a Russian prison

• Alexei Navalny, a top critic of Putin, is going on a hunger strike.
• He said he chose to go on a hunger strike after being denied medical help in a Russian jail.
• He is currently serving a two-and-a-half-year prison sentence for missing parole hearings.

Alexei Navalny announced he's going on a hunger strike in a Russian prison until he's able to see a doctor.

Navalny, a top critic of Russian President Vladimir Putin, is currently serving a two-and-a-half-year prison sentence for missing parole hearings while recovering from being poisoned with a Novichok nerve agent in Russia.

"The right to invite a specialist for examination and consultation exists for every convict. Even for me, despite the fact that I'm not guilty," he said on Twitter. "That's why I am urging that a doctor be allowed to see me, and until that happens, I am going on a hunger strike."

In a more detailed Instagram post, Navalny said he has been experiencing pain in his back, and has lost sensitivity in parts of his right leg and most of his left leg.

It's unclear what caused the pain he's experiencing.

He said in the Instagram post that he asked for a doctor to be called so he could get treatment and medicine, but his request was denied.

"In place of medical help, I am tortured with sleep deprivation (they wake me up 8 times a night), and the administration is encouraging the activist convicts (aka "goats") to intimidate prisoners so that they do not clean around or near my bed," he wrote. "They say just like this: 'Lesha, I'm sorry, but we are incredibly afraid. This is an area of Vladimir. The life of a prisoner is worth less than a pack of cigarettes.'"

Navalny began his 30-month prison sentence at the start of February.

Earlier this month he compared the living conditions inside the prison to a "concentration camp," and he said he's being monitored 24 hours a day.

He said that he's woken up every hour to ensure he has not escaped.

"Three things never cease to amaze me," he added. "The stars in the sky above us, the categorical imperative within us, and the amazing feeling when you run your palm over your freshly shaven head."

This is a developing story. Please check back for updates.