The United States has designated the ultranationalist Russian Imperial Movement (RIM) along with three of its leaders as terrorists, marking the first time the classification has been applied to a white supremacist group.

Ambassador Nathan Sales, the U.S. State Department's counterterrorism coordinator, on April 6 described the step as "unprecedented," saying in a statement that the movement had "innocent blood on its hands."

"RIM is a terrorist group that provides paramilitary style training to neo-Nazis and white supremacists, and it plays a prominent role in trying to rally like-minded Europeans and Americans into a common front against their perceived enemies," Sales said.

The movement describes itself as a "Russian Orthodox national-patriotic and monarchist organization" that aims to restore an autocratic monarchy in Russia. The group also seeks the declaration of Russia as a mono-ethnic state centered on what it classifies as the three branches of the Russian people -- Russians, Ukrainians, and Belarusians.

The movement has branches in St. Petersburg, Moscow, and Nizhny Novgorod and its military wing, the Imperial Legion, advertises training in hand-to-hand combat, martial arts, and tactical training.

Sales linked RIM to a series of bomb attacks targeting asylum seekers in Sweden in 2016-2017. Prosecutors in a case against three men accused of plotting the attacks alleged that the three had traveled to St. Petersburg, Russia, for military training carried out by the movement, according to The New York Times.

"The prosecutor who handled their case blamed RIM for radicalizing them and providing the training that enabled the attacks," Sales said in a statement.

Sales added that the battle against "white supremacist terrorism" would continue, and said that the administration of President Donald Trump would use all "counterterrorism tools to this fight."

It marks the first time the designation has been applied to a white supremacist group abroad, and comes after Trump signed an executive order in September 2019 that expanded sanctions for combating terrorism by allowing the terrorist designation to be applied to groups that provide training to terrorists.

With the designation in place, the U.S. Treasury Department announced that it had added RIM and three of its leaders to its Specially Designated Nationals List that blocks U.S. properties or assets that belong to the movement.

While the group is not considered to be sponsored by the Kremlin, it has openly recruited fighters for the Russia-backed separatists fighting against government troops in eastern Ukraine.

In addition to the movement itself, three members of the group's leadership were blacklisted individually.

The three, who all live in St. Petersburg, are RIM's leader, Stanislav Vorobyev, 59; the group's coordinator, Nikolai Trushchalov, 40; and Denis Gariyev, 42, who heads the Imperial Legion.

With reporting by The New York Times and Reuters