German federal prosecutors gave police the go-ahead to carry out raids on Monday on the homes and workplaces of two people suspected of planning "serious violence threatening to the state".
The suspects feared that Germany's refugee policies would impoverish the country and so had begun stockpiling food and ammunition and planning attacks, the federal prosecutor's office said in a statement.
"The suspects see the crisis they fear taking hold as an opportunity to capture left-wing political representatives and kill them with their weapons," it said.
The raids would be carried out in the eastern state of Mecklenburg-Vorpommern, it said.
Police would also carry out raids on people linked to the two suspects, but who were not themselves suspects, the prosecutor's office added. The suspects had been in contact with other people on chatrooms.
The prosecutor's office not immediately reachable by phone.