Authorities in Berlin said on February 4 that they foiled a terrorism plot in the German capital that was being planned by Algerian extremists with suspected links to Islamic State militants.
Berlin police spokesman Stefan Redlich announced the developments after police conducted a series of raids in Berlin in search of the suspects.
Two Algerian men were arrested on existing warrants in other cases -- one in Berlin and another at a refugee home in the western town of Attendorn.
Two other suspects, including an Algerian man who was at a refugee home in the city of Hannover, were questioned but not immediately charged.
The German news agency dpa quoted German security officials, who said phone calls were intercepted in which the suspects discussed potential targets in Berlin that included Checkpoint Charlie, the Cold War crossing point between East Berlin and West Berlin, and Alexanderplatz.
Germany has been on high alert since Islamic extremists killed 130 people in a series of attacks across Paris on November 13.