In this photo provided by the Babuskinsky District Court on Thursday, April 29, 2021, Russian opposition leader Alexei Navalny appears on TV screens via a video link from prison, during a hearing on his charges for defamation, in the Babuskinsky District Court in Moscow, Russia. The politician was convicted in February and ordered to pay a fine of 850-thousand rubles (the equivalent of $11,500). It was Navalny's first public appearance since his transfer to a penal colony last month.

MOSCOW — A top ally of imprisoned Russian opposition leader Alexei Navalny said Thursday that the network of the politician's offices in Russia is being closed as authorities seek to have it and Navalny's Foundation for Fighting Corruption outlawed as extremist groups.

Also on Thursday, Navalny made his first public appearance in weeks, facing a court via video link from behind bars. The politician looked gaunt after a three-week hunger strike, but still was able to slam the Kremlin in an emotional speech.

His embattled team has faced a major challenge this month. The Moscow prosecutor's office petitioned a court to declare both the regional offices and Navalny's anti-corruption organization as extremist groups, a label that would outlaw their activities, expose members and supporters to lengthy prison terms.

Leonid Volkov, who as Navalny's top strategist runs the regional offices, said Thursday that preserving the network of regional “headquarters” in its current state “is impossible” because of the extremism charges but rebranding them wouldn't help either.

“Unfortunately, it is impossible to work in these conditions. We're officially dismantling the network of Navalny's headquarters,” Volkov said on the messaging app Telegram.

Volkov's statement comes amid a sweeping crackdown on Navalny, President Vladimir Putin's fiercest critic, and his organizations. The politician is currently in prison, and dozens of his aides and associates have been under arrest, targeted for raids by law enforcement, or facing criminal charges.

While imprisoned, Navalny said he developed severe back pain and numbness in his limbs, and he spent more than three weeks on a hunger strike to protest authorities refusing to allow his doctor see him. Instead, they moved him to another prison with a hospital ward.

On Thursday, Navalny appeared in court via a video link from prison for an appeal of his conviction and fine for defaming a World War II veteran. The politician was convicted in February and ordered to pay a fine of 850-thousand rubles (the equivalent of $11,500).

Even though the quality of the video link was poor, it was visibly clear that the politician has lost a lot of weight. His head was shaven clean, and he wore a prison jacket with a black T-shirt under it, and glasses.