The background to this is the categorisation of the AfD-party as definitely right-wing extremist by the Federal Office for the Protection of the Constitution. (The Federal Office for the Protection of the Constitution [" Bundesamt für Verfassungsschutz" or "BfV"] is Germany's federal domestic intelligence agency.)
The official classification does not mean the AfD is banned, but it does come with some consequences.
The BfV said in its decision that the "ethnicity-and ancestry-based conception of the people that predominates within the party is not compatible with the free democratic order."
It cited the "xenophobic, anti-minority, Islamophobic and anti-Muslim statements made by leading party officials."
The party "aims to exclude certain population groups from equal participation in society, to subject them to treatment that violates the constitution, and thereby assign them a legally subordinate status," the agency said.
The BfV has already designated the AfD in the eastern German states Thuringia and Saxony-Anhalt as proven extremist groups.
The AfD has repeatedly courted controversy in recent years, with its senior officials dismissing Germany's Nazi era as "bird ****" in the nation's history which spans over 1,000 years, or claiming Adolf Hitler was "forced" to invade Poland.
Last year, AfD lawmakers were implicated in a report about an alleged plan for the mass deportation of millions of citizens.
In the past, there had already been similar accusations from US government circles as Rubio has now made.
Elon Musk met for a virtual conversation with AfD leader Alice Weidel during the current German parliamentary election campaign.
Musk called Weidel the most popular candidate in Germany and went on to say: ‘That's why I recommend voting for the AfD.’ According to the billionaire, only the AfD could save Germany. There is nothing outrageous about the AfD's positions, they are simply ‘common sense’, Musk claimed. Musk called Weidel a very sensible woman.
(With material from SPIEGEL and Deutsche Welle)