In the latest crackdown on the religious group, a Russian court has sentenced five Jehovah Witnesses to between six and six-and-a-half years in prison.

A court in the southwestern city of Volgograd sentenced the five individuals on September 24 after they were found guilty of participating in the activities of an “extremist” organization.

Sergei Melnik, 49, and Igor Yegozaryan, 50, were sentenced to six years in prison, while 50-year-old Vyacheslav Osipov and 43-year-old Denis Peresunko were handed sentences of six years and three months. Valery Rogozin, 59, was given a six-and-a-half year sentence.

According to the indictment, the believers “received recommendations from followers of the confession from abroad, were engaged in missionary work, conducted services, collected donations for them, and also shared religious literature with other members of the community.”

Russia labeled the Jehovah’s Witnesses an extremist group and banned it in 2017, leading to a wave of court cases and prison sentences against its members. For decades, the Jehovah’s Witnesses have been viewed with suspicion in Russia, where the dominant Orthodox Church is championed by President Vladimir Putin.

The Christian group is known for door-to-door preaching, close Bible study, rejection of military service, and not celebrating national and religious holidays or birthdays.

According to the group, dozens of Jehovah’s Witnesses have been either convicted of extremism or are in pretrial detention.

The Moscow-based Memorial Human Rights Center has recognized dozens of Jehovah’s Witnesses who have been charged with or convicted of extremism as political prisoners.