A Belarusian court Thursday gave lengthy criminal sentences to independent union leaders and activists. The prison terms add to existing crackdowns on dissent from the increasingly authoritarian government.

According to Radio Free Europe, leaders of the Union of Workers of Electronic Outposts Producing Industry (REP) Vasil Berasnyou and Henadz Fyadynich each received a sentence of nine years in prison for “creating an extremist organization and taking part in its activities.” Vyachaslau Areshka, an activist working with REP, was sentenced to eight years in prison for participating in activities which damage national security and incite social hatred.

REP was formed in 1990 following the collapse of the Soviet Union and is the largest industrial union in Belarus, with over 275,000 members. Union members are subject to increasing scrutiny and control by the Belarusian government, with many union members unjustly jailed or fined for participating in union activities.

Berasnyou, Fyadynich and Areshka’s prison terms are part of increasing authoritarianism in Belarus under the leadership of Alexander Lukashenko. Many in Belarus have disputed Lukashenko’s 2020 election win, including Berasnyou, Fyadynich and Areshka, who each claim the election was rigged. Lukashenko has responded to challenges of his authority by suppressing free speech and stripping birthright citizens of their rights and privileges. Leaders in the United States and the European Union refuse to acknowledge Lukashenko’s legitimacy as the leader of Belarus.