For the first time, the US has designated a white supremacist group as a terrorist organisation.
Trump administration officials said on Monday that the Russian Imperial Movement would be named a "Specially Designated Global Terrorist" organisation, which would result in sanctions against the group or any Americans that engage in transactions with its members.
The move reflects the administration's growing concern about white supremacist groups with links to foreign actors.
"This is the first time the United States has ever designated white supremacist terrorists, illustrating how seriously this administration takes the threat. We are taking actions no previous administration has taken to counter this threat," Mr Sales said in a teleconference with reporters.
"RIM is still very much in the business of providing training to like-minded Neo-Nazis and white supremacists across Europe. We know that they have recruited individuals from other countries in Europe and continue to do so."
The administration also placed individual sanctions on its leaders, Stanislav Anatolyevich Vorobyev, Denis Valliullovich Gariev and Nikolay Nikolayevich Trushchalov.
According to US officials, the Russian Imperial Movement is alleged to provide paramilitary training to neo-Nazis in camps it runs in St Petersburg, Russia. They are alleged to have trained two Swedes who bombed a café, and attempted to bomb a refugee campsite, in the Swedish city of Gothenburg in 2016.
The State Department also confirmed its awareness of reports the Russian Imperial Movement was among forces that fought in Ukraine on behalf of pro-Russian separatists.
Under the new sanctions, the Treasury Department's Office of Foreign Assets Control can seize any American property or assets belonging to the group and ban its members from travelling to the US. The US Justice Department will also be able to bring terror-related charges against anyone engaging in financial transactions with the group or its members.
In its annual terrorism report released in November, the State Department said ethnically and racially driven terrorism had risen alarmingly around the world since 2018, including in the US with the Pittsburgh Synagogue shooting.
"We know that white supremacists and other racially motivated terrorist organisations or networks communicate across international borders," Mr Sales said in November.
"We know that they are in a sense learning from their jihadist predecessors in terms of their ability to raise money and move money, in terms of their ability to radicalise and recruit, and so the State Department has been trying to mobilise international partners who see this threat the same way we do to take decisive action against these networks."