Sviatlana Tsikhanouskaya, a leader of the exiled opposition in Belarus, was found guilty of treason and “plot to seize power” and sentenced to 15 years in prison on Monday. Tsikhanouskaya claimed the judgment was retaliation for her efforts to advance democracy.

Tsikhanouskaya, a 40-year-old former English teacher, fled to the neighboring country of Lithuania in 2020 after competing against the country’s president, Alexander Lukashenko, in a contest that the official results indicated Lukashenko won handily.

She and the opposition said at the time that the results had been doctored to hand victory to Lukashenko instead of herself. Lukashenko, who has ruled Belarus with an iron hand for nearly 30 years, denied the claim.

Mass protests against Lukashenko, a close ally of Russia’s President Vladimir Putin, then erupted which his security forces suppressed, locking up his opponents or forcing them to flee.

The authorities put Tsikhanouskaya, the opposition’s de-facto head, on trial in absentia in January, accusing her and other opposition figures of trying to seize power in an unconstitutional way.

Belta, the state news agency, said a court in Minsk had sentenced Tsikhanouskaya to 15 years in a prison camp after finding her guilty of treason and conspiracy to seize power.

The same court handed an 18-year prison sentence to Pavel Latushko, a prominent member of the Belarusian opposition council, and 12-year jail sentences to three other activists convicted of being part of the same plot, Belta reported.

“15 years of prison. This is how the regime ‘rewarded’ my work for democratic changes in Belarus,” Tsikhanouskaya said on Twitter.

“But today I don’t think about my own sentence. I think about thousands of innocents, detained & sentenced to real prison terms. I won’t stop until each of them is released.”

According to rights advocates, there are approximately 1,500 political prisoners in Belarus.

Syarhei, Tsikhanouskaya’s own husband, was sentenced to 18 years in prison in 2021 after being found guilty of organizing public unrest in what she claimed was political retaliation and as part of Lukashenko’s campaign against anyone he perceived as a danger.

Ales Bialiatski, a human rights advocate and recipient of the Nobel Peace Prize, was given a ten-year prison term on Friday by a court in Minsk following a trial that was dubbed a “sham” in the West.

Since taking office in 1994, Lukashenko has charged that the West is attempting to destabilize Belarus and has vowed to sever all ties with any future uprisings.