A Russian court on Thursday ordered the release of a former mayor of the country’s fourth-largest city from custody pending an investigation and trial on the charges he is facing for criticizing Russia’s military operation in Ukraine.

Yevgeny Roizman, 59, who served as the mayor of Yekaterinburg from 2013 to 2018, was allowed to walk free, but was barred from attending public events, using the internet, telephone or mail and communicating with anyone other than his lawyers and close family.

Police arrested Roizman on Wednesday. He told reporters the case against him was launched under a new law adopted after Russia sent troops into Ukraine on Feb. 24. He faces up to three years in prison if convicted.

Russian courts fined Roizman three times earlier this year on similar charges, paving the way for a criminal case the law authorizes for repeat offenders.

Roizman, a sharp critic of the Kremlin, is one of the most visible and charismatic opposition figures in Russia. During his tenure as mayor, he enjoyed broad popularity in Yekaterinburg, a city of 1.5 million in the Ural Mountains.

His arrest triggered protests in his support, and one demonstrator was detained and ordered to serve 15 days in jail.

Roizman said the criminal charges against him were triggered by him calling the Kremlin’s actions in Ukraine an “invasion.” The Kremlin describes it as a “special military operation.”

Days after Russian President Vladimir Putin sent troops into Ukraine on Feb. 24, Russia’s Kremlin-controlled parliament approved legislation that outlawed alleged disparaging of the Russian military or the spread of “false information” about the country’s military operation in Ukraine.

Russian courts have increasingly handed out fines and, occasionally, prison terms to critics of Moscow’s action in Ukraine.

OVD-Info, a legal aid group that tracks political arrests in Russia, has counted 90 criminal cases on charges of spreading false information about the Russian military since Feb. 24.

According to Net Freedoms, another legal aid group focused on free speech cases, as of mid-August there were up to 4,000 administrative cases on charges of disparaging the armed forces.

Roizman remains one of the few visible opposition figures in Russia who had not yet been been jailed or fled the country under pressure from authorities. Two other prominent opposition politicians, Ilya Yashin and Vladimir Kara-Murza, were arrested under the same law as Roizman and face up to 10 years in prison, if convicted.

Similar charges were recently brought against eight close associates of imprisoned opposition leader Alexei Navalny, Putin’s most well-known critic. All of them have left Russia after they became the subjects of multiple criminal investigations.