The trial of 12 alleged far-right conspirators charged with planning attacks on politicians, asylum seekers and Muslims as part of a plot to overthrow Germany's democracy opened in Stuttgart on Tuesday.
Prosecutors claim that those accused, known as Gruppe S, planned to spark a "civil-war-like situation" in Germany.
The group's eight founding members had the goal of "destabilising and ultimately overthrowing" Germany's democratic order, authorities claim.
Members of the group are suspected of hoarding firearms, axes and swords for planned attacks, which were foiled by their arrests in February last year.
Prosecutors claim their targets included Muslims, political enemies and the German Parliament.
Eight of the men are charged with founding a terrorist organisation in September 2019, led by two suspects identified only as Werner S. and Tony E.
Three others are accused of membership of a terrorist organisation, while a 12th man is charged with supporting the group.
All of those charged are German citizens.
In order to plan their attacks, the group held regular meetings and communicated using messenger apps, the court was told.
The Gruppe S trial is taking place under high security at Stammheim Prison in Stuttgart and is expected to last several months.
Concern is growing in Germany over the rise of violent right-wing extremism.
The number of crimes committed by far-right suspects in the country jumped to its highest level for four years in 2020, provisional police figures released in February showed.
Interior Minister Horst Seehofer declared far-right extremism the "biggest security threat" facing Europe's largest economy.
A series of high-profile cases has rattled the country.
In January, German neo-Nazi Stephan Ernst was sentenced to life in prison for murdering pro-migration politician Walter Luebcke.
In February 2020, a far-right extremist killed 10 people and wounded five others in the central German city of Hanau.
And in 2019, two people were killed after a neo-Nazi tried to enter a synagogue in Halle on the Jewish holiday of Yom Kippur.
