MOSCOW -- Russia's Justice Ministry has filed a case with the Supreme Court to declare the administrative centre for Russia's Jehovah's Witnesses an extremist organization.

A court spokesperson was quoted by the state news agency RIA Novosti on Thursday as saying the case had been filed, but did not give details or say when the matter might be heard.

A statement from the religion's Russian branch said declaring Jehovah's Witnesses as extremist would "entail disastrous consequences for freedom of religion in Russia." The church estimates about 175,000 followers in Russia.

The Jehovah's Witnesses have come under increasing pressure in recent years, including a ban on distributing literature deemed to violate Russia's anti-extremism laws.

In February, investigators conducted an inspection of the religion's headquarters in St. Petersburg.