Aleksei A. Navalny, the most prominent challenger to the rule of President Vladimir V. Putin of Russia, appeared at a court hearing on Tuesday to face charges of embezzlement and contempt of court that could extend his imprisonment by 15 years.
The trial is starting as Mr. Putin has grabbed the world’s attention by engaging in a high-stakes standoff with the West over Ukraine. Mr. Navalny’s supporters said they believed the trial was deliberately scheduled to coincide with the crisis to divert attention away from his case.
The proceedings were held in a prison outside Moscow, where Mr. Navalny, who has accused Mr. Putin of ordering his security agencies to assassinate him, is serving a sentence that ends next year. The Kremlin has denied Mr. Navalny’s accusations.
Standing in a makeshift courtroom in his prison uniform, a visibly thinner Mr. Navalny accused the court of deliberately holding the trial in a penal colony hours away from Moscow to reduce media attention and obstruct the work of his lawyers, who were not allowed to bring their laptops with case materials.
“I am not afraid of this court, of the penal colony, the F.S.B., of the prosecutors, chemical weapons, Putin and all others,” Mr. Navalny said in court, according to a video of his statement. “I am not afraid because I believe it is humiliating and useless to be afraid of it all.”
Russian investigators have accused Mr. Navalny and his associates of creating his anti-corruption foundation for the purpose of embezzling people’s donations, court documents said. Investigators said that Mr. Navalny had published inquiries of “alleged corruption among government officials at various levels” to attract these donations. They said Mr. Navalny attempted to take part in the 2018 presidential election for that purpose. (Mr. Navalny was barred by Russian election officials from running for president.)
In particular, the investigators accused Mr. Navalny of stealing $35,000 from four people, who had testified against him. In a video published ahead of the trial, Mr. Navalny’s ally Ivan Zhdanov accused two of the four victims mentioned in the case of cooperating with the Russian government to “slander an innocent person in exchange for money.”
“These are people who were brought by the hand, given someone else’s money and told to make one payment,” said Mr. Zhdanov, adding that the criminal case was opened only a day after one of the four victims sent a donation to the foundation.
The other two people who testified against Mr. Navalny were pressured to do so, Mr. Zhdanov said. One is facing up to 10 years in prison, and the other had been under investigation over tax evasion, he said.
Over the past decade Mr. Navalny has built a political organization with offices in major cities. Despite growing police and government pressure, Mr. Navalny’s organization was able to consolidate some of the most vocal critics of Mr. Putin and helped organize some of the biggest street protests against his government.
In 2013, when the Russian government allowed Mr. Navalny to run for the post of mayor of Moscow, he came close to defeating the incumbent pro-Kremlin candidate, garnering more than 630,000 votes.
However, Mr. Navalny’s popularity grew hand in hand with the Kremlin’s decreasing tolerance for his activities.
Mr. Navalny was arrested for violating parole at a Moscow airport after returning to Russia last year from Germany, where he was recovering from poisoning he said was organized by the Russian government. Ever since his return and subsequent sentencing, Mr. Navalny and his associates and supporters have faced increased pressure from the Russian government.
Multiple criminal cases were opened against him and his allies. His anticorruption foundation and his political organization were declared extremist and banned. Many of his allies had to flee Russia. Some were arrested and remain in custody.
“I insulted your dark lord Putin by not only surviving, but by returning,” Mr. Navalny said in his statement to the judge and prosecutors. “Now, he will increase my prison terms forever,” he added, referring to Mr. Putin.
“But I believe that the worst real crime I could commit is if I get afraid of you and who stands behind you,” he said addressing the judge and prosecutors.
The next hearing in his case is scheduled for Monday.