MOSCOW - A Belarusian court convicted popular blogger and leading opposition figure Sergei Tikhanovsky of inciting mass unrest and social hatred and sentenced him to 18 years in prison on Tuesday after a closed 173-day trial. It is the latest in hefty sentences of political rivals who challenged President Alexander Lukashenko in the 2020 elections.

Tikhanovsky announced plans to run against Lukashenko before the August 2020 elections but was arrested, jailed and barred from running, prompting his wife Svetlana Tikhanovskaya, to take his place, forming an opposition alliance with two other figures, Maria Kolesnikova and Veronika Tsepkalo.

Kolesnikova was jailed for 11 years in September. Another of Lukashenko’s opposition rivals who announced plans to run in the election, Viktor Babariko, was jailed for 14 years in July.

Street protests broke out after Lukashenko, who has been in power since 1994, was declared the winner in the elections, in results rejected by the opposition. Facing the strongest challenge to his rule, he launched a brutal crackdown, which eventually succeeded in crushing the protests. Thousands of Belarusians have fled into exile.

Belarusian rights group Viasna says 920 political prisoners are being held by the regime. People have been arrested for a tweet or for displaying the red and white flag adopted by the opposition.

In a sign to his supporters, Tikhanovsky managed to display the red and white colors as he was led into court with his hands cuffed behind his back Tuesday, video on independent Belarusian media showed. He held a sheath of papers, including a red folder sandwiched between white papers.

After the sentence for her husband was handed down, Tikhanovskaya tweeted that the Belarusian opposition would not give up its struggle.

“The dictator publicly takes revenge on his strongest opponents,” Tikhanovskaya tweeted. “While hiding the political prisoners in closed trials, he hopes to continue repressions in silence. But the whole world watches. We won’t stop.”

Tikhanovskaya was forced to leave Belarus following the elections in 2020 after leading the initial protests over the election result, and attempting to lodge a complaint against it at the Central Election Commission. Her ally, Tsepkalo, fled earlier, fearing arrest.

The election was condemned as fraudulent by the State Department and the European Union. Tikhanovskaya, who ran for office on a platform that called for free elections, is recognized in Europe and the United States as the winner.

The United States and the E.U. have imposed sanctions on Lukashenko over the election, political violence against protesters and the forced landing of a Ryanair plane to arrest opposition activist Roman Protasevich.

Tikhanovsky, 43, a former night club owner, is famous in Belarus for his YouTube channel “Country for Life,” based on the lives of ordinary Belarusians. He traveled around the country interviewing people about their daily problems and small business executives about the corruption and bureaucratic red tape they faced.

He was arrested in May 2020 over mass rallies he organized to collect signatures needed to run for president against Lukashenko. Prosecutors accused him of inciting mass unrest and whipping up social hatred.

When the trial of Tikhanovsky and five others began in June this year, video showed the handcuffed defendants placed in a cage in a small courtroom.

“I don’t know what to expect,” tweeted his wife Tikhanovskaya at the time, “but definitely not justice.”

The court also sentenced another popular blogger Ihar Losik to 15 years in prison Tuesday. Others handed long sentences were: former presidential candidate Nikolai Statkevich who was given 14 years; and former opposition activists, Vladimir Tsyganovich, 15 years; Artyom Sakov, 16 years; and Dmitry Popov, 16 years.

“Long live Belarus,” Statkevich said as he was led into court handcuffed for Tuesday’s sentencing, according to video shown on Belarusian independent media.

Losik worked for a popular Telegram channel, Belamova before his arrest in June last year, and also reported for Radio Free Europe/Radio Liberty.

RFE/RL president Jamie Fly condemned the convictions, adding that Losik’s treatment by authorities was “reprehensible. The closed-door trial he and his co-defendants have endured for the past five months has been an outrageous travesty of justice.”

Fly said Losik had been under severe physical and psychological pressure in jail and had been allowed to see his wife only once, and had been denied visits from his daughter and his parents. He has mounted two hunger strikes.

“Prison authorities have also sought to affect Losik’s mental state while in detention with frequent transfers to different cells and by denying mail privileges for extended periods of time,” Fly said.

Franak Viacorka, senior adviser to Tikhanovskaya, said the hefty sentences were “just numbers” and called the trial a “farce and shame for the regime.”

“We’ll release them,” he said in a tweet. “For 173 days, the regime ran a closed trial, even the relatives weren’t allowed in the courtroom.”

He said the trial was closed “because it recognizes how powerful these people are.” He said Lukashenko was “scared of all of them, even when they are behind bars.”

He added that Losik was “only guilty only of believing in free democratic Belarus. This is his thought crime.”