TALLINN, Estonia (AP) — Hundreds of protesters clashed with police in the Russian region of Bashkortostan on Wednesday in a rare display of public outrage after a court convicted a local activist and sentenced him to prison, media reports and rights groups said.

The unrest — one of the largest reported demonstrations since the war in Ukraine began in 2022 — erupted amid the trial this week of Fail Alsynov in the town of Baymak, about 1,400 kilometers (870 miles) southeast of Moscow, in the southern Ural Mountains.

Several thousand people had gathered outside the courthouse to support Alsynov, who was convicted of inciting hatred and sentenced to four years in prison, according to OVD-Info, a Russian rights group that tracks political arrests and offers legal aid.

Police used tear gas and batons to disperse the crowd, which chanted “Fail, we stand with you!” along with “Freedom!” and “Disgrace!” They demanded the ouster of Bashkortostan’s governor and hurled snowballs at officers, OVD-Info and local media reported. Dozens of people were detained and injured, OVD-Info said.

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Alsynov was a leader of a group that advocated for preserving the Bashkir language and culture, and protested limestone and gold mining operations in the region. The group, called Bashkort, was outlawed as extremist in 2020.

He faced charges after a speech last year in an unsanctioned rally against gold mining, Russian independent news outlet Mediazona reported.

Bashkortostan Gov. Radiy Khabirov reportedly personally filed a complaint against Alsynov, alleging the speech denigrated other nationalities and fomented anti-government actions.

Alsynov maintained his innocence, telling the RusNews outlet after the sentencing that he has “always fought for justice, for my people, for my republic.”

Hundreds — and possibly thousands — of Alsynov’s supporters initially gathered Monday in front of the courthouse when closing arguments were delivered in the case. Russian independent news outlet Agentstvo reported Monday that it was one of the biggest protests in Russia since the invasion of Ukraine, which has brought about more restrictive laws and an intensified crackdown on dissent.

The demonstrators returned to the courthouse Wednesday for the sentencing. Video posted by Russian media showed crowds facing off with riot police in a snowy rural landscape.

Russia’s top law enforcement agency, the Investigative Committee, said it opened a criminal case on the charges of fomenting mass riots and assaulting police officers.

Several social media pages that reported on the protests or served as a platform for the local community have been blocked, according to Meduza, a popular Russian independent news outlet.

The protests come just two months ahead of a presidential election that is widely expected to give Vladimir Putin his fifth term in office.

Putin, 71, is able to run again after 24 years in power due to a constitutional reform he orchestrated in 2020, which reset presidential term limits. With the opposition largely suppressed and independent media banned or restricted, his reelection is all but assured.

There was no immediate comment on the protests from the Kremlin.

Putin is running as an independent candidate and not on a party ticket, and is required to collect at least 300,000 signatures in support of his candidacy. His campaign office reported Wednesday that 2.5 million signatures have already been collected.