Russia’s Supreme Court has designated the Jehovah’s Witnesses as an extremist organization and ordered the state to seize the religious group’s property.

In a Thursday ruling, the court upheld a government request to ban the group from operating on Russian territory. The decision could place more than 170,000 Russian adherents of the Jehovah’s Witnesses, a U.S.-founded Christian denomination that preaches non-violence, in the same category as militant groups Al Qaeda and the so-called Islamic State.

The decision came after six days of hearings spread over the last two weeks, during which the court reviewed a claim submitted by the Ministry of Justice in Moscow. The ministry sought to liquidate the Administrative Center of Jehovah’s Witnesses in Russia, as well as 395 local branches throughout the country.

The ministry was investigating the Jehovah’s Witnesses’ Russian headquarters near St. Petersburg over the last year and claimed it discovered violations of a Russian law banning extremism.

Like Mormons, Seventh-Day Adventists and other religious minorities in the country, Jehovah’s Witnesses have come under intense scrutiny under Russian anti-extremism laws that ban proselytizing and curtail the dissemination of religious literature.

The government has cracked down on the group in recent years, imposing fines on congregations and occasionally arresting leaders perceived to be stoking anti-government sentiment.

In its claim to the Russian Supreme Court, the ministry accused Jehovah’s Witnesses of disseminating “extremist” pamphlets and said the center and all regional facilities should be “liquidated.”

One pamphlet the ministry reportedly took issue with quoted the novelist Leo Tolstoy and described the beliefs of the Russian Orthodox Church as superstition and sorcery, according to the BBC.

Thursday’s ruling will go into effect immediately.

Yaroslav Sivulskiy, a spokesman for Jehovah’s Witnesses in Russia, said he was “greatly disappointed” by the court’s decision.

“We will appeal this decision, and we hope that our legal rights and protections as a peaceful religious group will be fully restored as soon as possible,” Sivulskiy said in a statement.