A pair of Jehovah's Witnesses has been convicted of extremism in Russia and four more arrested, one of whom reported being tortured in custody.

The married couple were handed fines for engaging in extremist activities related to their membership in the religious group.

Earlier this week the police raided homes of Jehovah's Witnesses in southern Siberia and arrested four members of the group.

Russia officially banned Jehovah's Witnesses in 2017, declaring the group an extremist organization.

Crackdowns have since intensified. On February 7 authorities in Russia announced that they had blacklisted more than 200 Jehovah's Witnesses, adding them to a register of extremists and terrorists.

The Associated Press reports that the Kremlin has actively used vaguely worded extremism laws to crack down on opposition activists and religious minorities.

Twenty-six Jehovah's Witnesses have now been convicted since the 2017 declaration. Nine have been sentenced to prison, and over 300 people are under criminal investigation.