MOSCOW (Reuters) - A Russian court sentenced a Jehovah’s Witness adherent on Tuesday to six years in jail on a charge of organizing an extremist group, said the Investigative Committee, which handles major crimes.

Russia has targeted followers of the Jehovah’s Witnesses, a denomination of Christianity, since a 2017 ruling by the Supreme Court declared the group an extremist organization and ordered it to be disbanded.

Sergey Klimov, 49, was head of the Jehovah’s Witnesses in the Siberian city of Tomsk, the Investigative Committee said in a statement.

He is the eighth Jehovah’s Witness member to receive a prison sentence since the law came into effect, the group said. A total 284 adherents are under investigation, of whom 46 are in detention and 23 are under house arrest.

Six Jehovah’s Witness followers were jailed in late September for extremism, receiving jail sentences of between two and three-and-a-half years, while a Danish builder, Dennis Christensen, was sentenced to six years in February.

284 adherents are under investigation, with 46 being held in detention and 23 under house arrest

The U.S.-headquartered Jehovah’s Witnesses have been under pressure for years in Russia, where the dominant Orthodox Church is championed by President Vladimir Putin.

Orthodox scholars have cast them as a dangerous foreign sect that erodes state institutions and traditional values, allegations they reject.