An initial appeal will be made to the Supreme Court’s appellate division, Mr. Zhenkov said, and if that fails, Jehovah’s Witnesses will take the case to the European Court of Human Rights, in Strasbourg, France.

Hard-line followers of Russia’s dominant faith, the Orthodox Church, have lobbied for years to have Jehovah’s Witnesses outlawed or at least curbed as a heretical sect, but the main impetus for the current campaign to crush a Christian group active in Russia for more than a century seems to have come from the country’s increasingly assertive security apparatus.

Founded in the United States in the 19th century, Jehovah’s Witnesses has its worldwide headquarters in the United States and, along with all foreign-led groups outside the control of the state, is viewed with deep suspicion by Russia’s post-Soviet version of the KGB: the Federal Security Service, or F.S.B.

Summing up the Justice Ministry’s case against the denomination, the ministry’s representative, Svetlana Borisova, told the Supreme Court on Thursday that Jehovah’s Witnesses had shown “signs of extremist activity that represent a threat to the rights of citizens, social order and the security of society.”

During six days of hearings over two weeks, lawyers and witnesses for the religious group repeatedly dismissed the extremist allegation as absurd, arguing that reading the Bible and promoting its nonviolent message could in no way be construed as extremist.