German police have detained four people accused of plotting to create "civil war conditions" so they could eventually overthrow democracy.
Prosecutors say the group, linked to far-right and anti-Covid movements, were planning to destroy power stations to cause a nationwide blackout.
They also wanted to kidnap Germany's health minister, who backed the country's strict coronavirus controls.
The group are due before a judge on Thursday.
A fifth suspect remains at large.
In total, investigators have identified 12 people they believe were connected to the group, which used the Telegram messaging app to communicate.
The gang - who used the name United Patriots - were part of the Reichsbürger (Citizens of the Reich), whose members reject the German state as a legal entity, and opposed the German government's anti-Covid measures, the prosecutors said.
According to TV news programme Report Mainz, the group wanted to attack substations and power lines, destroying the country's energy infrastructure.
In a statement, the prosecutors office said the aim was to cause a long-lasting nationwide power failure "intended to cause conditions similar to civil war and ultimately to overthrow the democratic system in Germany".
A number of high profile people were allegedly also marked out as potential kidnap victims.
Two of the suspects are believed to have been planning an attack on Health Minister Karl Lauterbach.
Mr Lauterbach said the plot showed that coronavirus protests had become radicalised, and promised that his work would not be affected.
"There are forces that intended to destabilise the state and democracy. They are using the Covid protests. This is a small minority in our society but they are highly dangerous," he told a news conference.
The group were arrested in a series of raids on Wednesday, with police also seizing numerous guns including a Kalashnikov.
They also found gold bars and cash in euros and foreign currency totalling almost €20,000 (£16,600; $21,800).
The group, aged 41 to 55, are accused of preparing a serious act of violence that endangers the state and of violating a weapons control act.