Navalny appears in a Russian court to face new charges of extremism.

A fresh trial for Aleksei A. Navalny, the incarcerated leader of Russia’s opposition, commenced on Monday, potentially resulting in additional decades being added to his current prison sentences due to several extremism charges.

Although the charges were filed at a Moscow district court, the trial took place approximately 150 miles east of the capital in the penal colony where Mr. Navalny has been detained since 2021. Journalists, located in a separate room, had access to a video feed from the hearing room in the prison, but Mr. Navalny was barely visible or audible, as reported by a journalist from the Mediazona news outlet.

The new charges brought forth by the Basmanny District Court included allegations of incitement and financing of extremism, as well as “rehabilitating Nazism.” Mr. Navalny previously stated that he was given minimal time to review the extensive case materials, consisting of around 200 volumes or nearly 4,000 pages. He and his supporters have consistently asserted that all the charges against him are politically motivated.

If Mr. Navalny is convicted—a rare occurrence in Russian courts, particularly in cases involving opposition figures—the verdict could add an additional 30 years to his current prison term.

At the age of 47, Mr. Navalny has already been sentenced to nine years in prison for various offenses, including parole violations, fraud, and contempt of court.

Mr. Navalny, known for his sharp wit and charismatic persona, has exposed corruption within the Kremlin elite through his investigations, making him a distinctive political force in Russia. His ability to mobilize people across the country to protest against the government is remarkable.

Daniel Kholodny, a former technical director of Mr. Navalny’s YouTube channel, is also standing trial alongside him, facing charges of participating in and financing extremist activities. Throughout the trial, they are being represented by three lawyers.

According to Kira Yarmysh, Mr. Navalny’s spokesperson, at least 15 activists who collaborated with him are confronting similar charges. Many of these individuals have sought refuge in exile.

Last week, two former associates of Navalny received lengthy prison sentences, marking the first convictions of Navalny activists since the Russian government declared his grassroots anti-corruption group an “extremist organization” in 2021. Lilia Chanysheva, the head of Mr. Navalny’s office in the central Bashkortostan region, was sentenced to seven and a half years behind bars, while her former colleague, Rustem Mulyukov, received a two and a half-year sentence on comparable charges.

In 2021, Mr. Navalny was arrested upon his return to Russia from Germany, where he had recuperated from a nearly fatal poisoning that was widely attributed to the Kremlin. The Russian government has consistently denied any involvement in the incident.

The documentary film “Navalny,” which won an Academy Award this year, implicated several agents from the Russian state security service, the FSB, in the attack.

Mr. Navalny’s parents, Anatoly and Lyudmila, requested to attend the hearing in person on Monday but were also relocated to a separate room, as reported by Mediazona. During the proceedings, Mr. Navalny’s initial request to the judge was to allow his parents into the hearing, and the judge stated that he would consider it later