MOSCOW -- Alexei Navalny voiced hope for a better future in Russia as his supporters defied a crackdown on dissent to hold pickets and demonstrations to mark the imprisoned opposition leader's 47th birthday on Sunday, with at least 90 people reported arrested.
Navalny is serving a nine-year sentence for fraud and contempt of court, charges he says were trumped up to punish him for his work to expose official corruption and organize anti-Kremlin protests.
He is facing a new trial on extremism charges that could keep him in prison for decades. Kremlin critics view the case as another Russian government attempt to isolate President Vladimir Putin's most prominent foe.
Navalny's associates called for demonstrations to show support for him in Russia and abroad on Sunday.
Risking their own prison terms, some Navalny supporters in Russia marked his birthday by holding individual pickets, while others painted graffiti. At least 90 people were detained, according to the OVD-Info group that monitors political arrests.
Police beefed up their presence in downtown Moscow and moved quickly to round up those who tried to stage individual pickets on Pushkin Square and elsewhere in the capital.
One man managed to throw around leaflets before being whisked away.
A woman holding a small black balloon with the words "Happy Birthday!" who was clad in a hoody with "You aren't alone" written on it was among those detained. She asked officers why they were detaining her, but they didn't answer.
Navalny's supporters also showed up in St. Petersburg and other Russian cities, holding one-person pickets and leaving signs and graffiti in Navalny's support.
Pro-Navalny demonstrations were held in several European cities.
Navalny said in a social media post his allies released that he would obviously prefer to spend his birthday with a family breakfast, kisses from his children and gifts, but "life is such that social progress and a better future can only be achieved if a certain number of people are willing to pay for the right to have beliefs."
"The more there are such people, the smaller the price each has to pay," he said. "And a day will certainly come when it will be routine and not dangerous at all to tell the truth and stand for justice in Russia."
Navalny was arrested in January 2021 upon returning to Moscow after he recuperated in Germany from nerve-agent poisoning that he blamed on the Kremlin.
He initially received a 2 1/2-year prison sentence for a parole violation. Last year, he was sentenced to nine years for fraud and contempt of court. He's serving time at a maximum-security prison 250 kilometers (150 miles) east of Moscow.
The extremism charges against Navalny, which could keep him in prison for 30 years, relate to his anti-corruption foundation and statements by his top associates. His allies said the charges retroactively criminalize all the activities of Navalny's foundation since its creation in 2011.
The new accusations come as Russian authorities are conducting an intensified crackdown on dissent during the fighting in Ukraine, which Navalny has harshly criticized.
A Moscow court scheduled a preliminary hearing Tuesday to discuss technical issues related to a new trial of Navalny, rejecting a request by his lawyers for more time to examine voluminous new charges that he rejected as "absurd."
Navalny also has cited an investigator telling him that he also would face a separate military court trial on terrorism charges that potentially carry a life sentence.
He said in a social media post Sunday that he sees his prison term "just as an unpleasant part of my favorite job" and thanked his supporters.
"My plan for the previous year was not to grow brutal and embittered and not to lose the nonchalance of behavior -- this is where defeat begins," he wrote. "And if I succeeded, it was only thanks to your support."
