A former mayor of Russia's fourth-largest city was ordered to spend 14 days in custody on Thursday pending his trial on charges that could entail a longer prison term, part of authorities' efforts to muzzle dissent.

Yevgeny Roizman, a sharp critic of the Kremlin, is one of the most visible and charismatic opposition figures in Russia. He enjoyed broad popularity while serving as mayor of Yekaterinburg, a city of 1.5 million people in the Ural Mountains.

Last year, Roizman, 60, who was mayor from 2013 to 2018, faced accusations of discrediting the Russian military and was barred from attending public events, using the internet, telephone or mail and communicating with anyone other than his lawyers and close family pending his trial.

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Police arrested Roizman on Thursday on charges of reposting material containing a reference to the organization led by jailed Russian opposition leader Alexei Navalny that was banned by authorities. Roizman rejected the accusations during a court hearing in Yekaterinburg after his detention and insisted that he wasn't even registered on that social network. His lawyer argued that the repost was done by members of one of his numerous support groups.

Despite Roizman's arguments, the court in Yekaterinburg sentenced him to 14 days in jail. The ruling would bar him from running in the elections set for later this year, although Roizman hasn't voiced an intention to join the race.

Yevgeny Roizman

Former Yekaterinburg, Russia, Mayor Yevgeny Roziman, a prominent Putin critic, has been ordered to spend at least 14 days in jail pending trial. (AP Photo/Vladimir Podoksyonov)

It was unclear whether the authorities would use his conviction to keep him behind bars for breaking the order not to use the internet. It was also unclear what the sentence would mean for his separate trial on charges of discrediting the military that is expected to open later this month.

Courts repeatedly fined Roizman last year on charges of discrediting the military, and he could face up to three years in prison for a repeat offense if convicted.

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Days after Russian President Vladimir Putin sent troops into Ukraine last year, Russian lawmakers approved legislation that outlawed the alleged disparagement of the Russian military or the spread of "false information" about the country’s military operation in Ukraine. Courts across the country have increasingly handed out prison terms to critics of Moscow’s actions in Ukraine.

Roizman was one of the few visible opposition figures in Russia who hadn't yet been been jailed or fled the country under pressure from authorities. A prominent opposition politician, Ilya Yashin, was sentenced to 8½ years in prison on charges of discrediting the military, and another top opposition figure, Vladimir Kara-Murza, has been jailed on the same charges and is now facing trial.

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Kara-Murza's health has deteriorated significantly behind bars, his lawyer Vadim Prokhorov said. The politician couldn't attend a court hearing on Thursday and it was canceled, Prokhorov said on Facebook. The defense will work on getting the politician to a civilian hospital for examination and treatment and on releasing him from custody pending trial, Prokhorov said.