MOSCOW — Russian opposition leader Alexei Navalny appeared in court via video Thursday, decrying Russia's political leaders as traitors as his headquarters and regional offices disbanded while facing a move to ban them as extremists.

Leonid Volkov, who oversees nearly 40 regional offices in Navalny’s network, said it was not safe to continue to operate with a court almost certain to confirm the ban sought by prosecutors.

Navalny, looking thin, took part in a video court session for the first time since ending a more than three-week hunger strike in prison to demand better medical treatment.

Addressing the judge, he said the Moscow prosecutor’s motion to ban several of his organizations was an attempt “to make extremists of me and people like me, patriots of the country who protect the country from you traitors.”

Calling President Vladimir Putin a “naked king,” he said that “20 years of his fruitless rule have come to this result: The crown is slipping off his ears, there are lies on television, we have wasted trillions of rubles and our country continues to slide into poverty.”

He accused Putin and his government of “turning Russians into slaves.”

The case on the extremist designation, to be heard by a closed Russian court, will rule on whether three organizations, including Navalny’s Anti-Corruption Foundation, qualify as extremist groups. If confirmed, it would mark the Kremlin’s most sweeping effort to crush Navalny’s organization and would mean that his staff and supporters could face prison time.

A ban would also stop Navalny’s organization from selling merchandise and undercut its efforts to raise money through crowdfunding.

The opposition’s move to disband Navalny’s headquarters even before the court decision was based on its view that a ban was inevitable and that disbanding was necessary to protect staff members.

A post on Navalny’s webpage Thursday said there was “no doubt” that the court would ban the organizations as extremist, although it asserted that the prosecution presented no evidence to justify the ban.

“Maintaining the work of Navalny’s Headquarters network in its current form is impossible,” Volkov wrote Thursday on Telegram.

If the court bans the organizations, they would be barred from using platforms such as YouTube and Instagram — tools used with devastating effect to spread their allegations of corruption by Russian officials, members of Putin’s United Russia party, oligarchs and the president himself. Supporters retweeting or reposting such material could be prosecuted.

In the past, Navalny’s Anti-Corruption Foundation has published hard-hitting reports on corruption, including “Putin’s Palace: History of the World’s Largest Bribe,” viewed on YouTube more than 116 million times.

“The prosecutor’s office writes in plain black and white text: ‘We forbid you to fight corruption. The fight against corruption, your participation in elections and rallies is ‘extremism,’ ” said the post on Navalny’s website Thursday.

Much of the evidence in the court case is a state secret, meaning the Russian public may never learn the basis of the case. Ivan Pavlov, an attorney for Navalny’s organizations, said that the classified materials in the case added up to 900 pages but that it was not clear why they were classified, and announced plans to challenge the secrecy classification.

Navalny is serving a jail term of more than 2½ years in a case he calls political. He was arrested on his return from Germany, where he received treatment last year after being poisoned in August with a banned chemical nerve agent in an attack that the United States and the European Union have blamed on the Russian state.

In his court appearance appealing the libel conviction, Navalny asked his wife, Yulia, to stand up so he could see her via video.

“I’m awfully glad to see you,” he said, and she responded that it was good to see him, too. He said that he weighed 158 pounds and that “I certainly look like a skeleton.”

Navalny, 44, announced an end to his hunger strike last weekend after he received access to doctors he trusted. He was given four spoons of porridge Wednesday and six Thursday, he said. He said his daily intake was rising from 370 calories Wednesday to 450 Thursday and 530 Friday.

Meanwhile, news emerged Thursday of another criminal charge against Navalny and his allies Volkov and Ivan Zhdanov, director of the Anti-Corruption Foundation. The case was initiated in February and accuses them of setting up an organization that infringes on the person and rights of citizens. The alleged offense carries a penalty of up to four years in prison. Volkov, Zhdanov and other Navalny allies have fled the country, while dozens have been arrested.

“The encroachment on the person of Putin and his friends lies in the fact that the Anti-Corruption Foundation and headquarters have been talking about his theft for years,” said the post on Navalny’s website Thursday. “Obviously, Putin and his officials sincerely believe that stealing is their legal right. And the Anti-Corruption Foundation and headquarters infringe on this right when they fight against their theft.”

Earlier this week, the court suspended the activities of the Anti-Corruption Foundation and Navalny’s headquarters pending the court’s decision on the request for a ban. In a bizarre twist, the Moscow court suspended “certain activities” of the Anti-Corruption Foundation on Tuesday, but its news service declined to list them because they are secret.

Navalny’s lawyers said the suspension meant the foundation was barred from organizing rallies, posting on social media networks and using its bank deposits except to pay taxes. Lawyers plan to appeal the suspension.

After the suspension, many branches of Navalny’s headquarters announced they were closing, posting messages that it would be dangerous for staff members and supporters to continue work “in the old format.”

Volkov said Thursday that he and other Navalny supporters are not giving up, just changing course.

“All our hellish work over these four years and all your support was not in vain,” he said. “You and I have sown the seeds of freedom all over Russia. The seeds will sprout. The seeds will germinate. There is no longer a network of Navalny’s Headquarters, but there are dozens of powerful and tough regional politicians, and thousands of their supporters. There are strong and independent political organizations which will engage in investigations and elections, public campaigns and rallies.”

OVD-Info, a private legal rights group, reported that Russian authorities have arrested 115 people since last week’s demonstrations in Russian cities in support of Navalny.