In the background is a picture of the airport, with fighters and the sentence: "What your brothers in Belgium managed to do, you can do as well," GA wrote.
Asked if authorities were aware of the photo montage, a spokesperson of the North Rhine Westphalia (NRW) Interior Ministry said: "We take this propaganda of ISIS very seriously." Security remains vigilant even if authorities in NRW have no concrete information on planned attacks in this area.
Read alsoISIS chief executioner threatens further attacks on the West in new videoAccording to information from the "Rheinische Post" newspaper, federal police and German federal crime investigators are evaluating the montage.
General-Anzeiger has information from reliable sources investigating the incident that an Islamist from the Bonn area has threatened with an attack on Bonn. Sources say the man has travelled to Syria and is now planning to return. His exact location at the moment is unclear. Special forces are said to be searching for him. According to the sources, there is a warrant out for his arrest.
