A Belarusian court on Wednesday sentenced a journalist and prominent member of the country’s sizable Polish minority to eight years in prison, amid an ongoing crackdown on critics of authoritarian President Alexander Lukashenko’s regime.

Andrzej Poczobut, 49, was found guilty of harming Belarus’ national security and “inciting discord” in a closed trial held in the western city of Grodno. Poczobut, a journalist for the influential Polish newspaper Gazeta Wyborcza and a top figure in the Union of Poles in Belarus, has been behind bars since his detention in March 2021.

He reported extensively on the mass protests that gripped Belarus for weeks in 2020 following a presidential election that gave Lukashenko, in power since 1994, a new term in office, but that was widely regarded by the opposition and Western countries as fraudulent.

The indictment against Poczobut referenced his coverage of the protests, along with his statements in defense of ethnic Poles in Belarus and reference to the 1939 Soviet invasion of Poland as an act of “aggression,” as evidence that he was guilty of the charges.

Polish Prime Minister Mateusz Morawiecki in a Tweet Wednesday condemned the “inhumane decision by the Belarusian regime” and vowed to “do everything to help the Polish journalist bravely fighting for the truth.”

Poland’s foreign ministry summoned the top Belarusian diplomat in Warsaw, Alexander Tshasnouskyy, to protest the verdict.

Poland demands the release of Poczobut and of all political prisoners in Belarus and urges Minsk to respect international laws and put an end to actions against the Polish minority, the ministry said in a statement.