German police have arrested a man on suspicion of sending dozens of threatening letters to politicians, lawyers and journalists.
The letters contained "hateful, insulting and threatening content" and were signed with the acronym of a neo-Nazi group, officials said on Tuesday
A 53-year-old suspect was detained after a search of his apartment in the capital city Berlin, prosecutors said.
The unemployed man accused of being behind the campaign has previous convictions for "numerous crimes, including ones motivated by right-wing ideology," prosecutors said.
Police say the suspect had sent almost 100 letters to people and organisations across Germany and Austria since August 2018.
The letters were mainly addressed to public figures known for their commitment against racism and anti-Semitism, as well as to immigrants themselves.
Threats were written under the pseudonym NSU 2.0 - a reference to the far-right National Socialist Underground movement that was responsible for a string of violent crimes and assassinations between 1998 and 2011.
The NSU group was behind the racially motivated killings of nine men with immigrant backgrounds - eight Turks and one Greek - and a policewoman. The main surviving member of the gang was sentenced to life imprisonment in 2018.
German media have reported that investigators think the suspect may have obtained personal data on the people he targeted from official records or Darknet forums.
Security agencies have warned of the growing threat of violent far-right extremism in Germany.
On Tuesday, Interior Minister Horst Seehofer said far-right crime had risen 5.65% in 2020, accounting for more than half of all "politically motivated" offenses.
"This shows again that right-wing extremism is the biggest threat for our country," Seehofer told reporters while announcing the annual statistics.
Anti-Semitic crimes in Germany were also up 15.7% in 2020 compared to 2019 - 94.6% of which were committed by a far-right suspect.
Meanwhile, the country also recorded a 72.4% increase in anti-immigrant crimes, Seehofer added.