The Supreme Court of Russia, acting on a request by the Prosecutor General's Office, has designated Ukraine's ultra-right Azov Regiment as a "terrorist" organization.
The court announced the decision on Tuesday against the group, one of the most prominent Ukrainian military formations fighting against Russia in eastern Ukraine.
The court ruled to "recognize the Ukrainian paramilitary unit Azov a terrorist organization and to ban its activities on the territory of the Russian Federation," the judge was quoted by the state news agency TASS as saying.
The ruling takes immediate effect.
The Azov Regiment is a far-right volunteer group that is part of Ukraine's National Guard. Formerly known as the Azov Battalion, it espouses an ultranationalist ideology that U.S. law enforcement authorities have linked with neo-Nazi extremism. But supporters see it as a patriotic and effective part of the country’s defense forces.
Russia falsely claims that Ukraine is controlled by Nazis and used that charge as one of the justifications for its unprovoked invasion of the country.
Some relatives of Azov Regiment soldiers have worried that the court's designation could mean that those who surrendered to Russia, or were captured by Russian forces, could now be tried as terrorists.
The Azov Regiment fought Russian troops for months in the southern city of Mariupol before around 2,500 of its fighters surrendered in mid-May.