(ANSA) - BELGRADE, DEC 22 - "This year, we have received over a thousand reports of suspicious drone flights. The issue is that these are frequently visual sightings, and thus errors can occur; for example, in bad weather, the lights seen can be confused with those of an aeroplane. This means that they are not always drones, and not all drones are dangerous," Holger Muench, President of the Federal Criminal Police Office, said in an interview with the German newspaper Bild. He did, however, emphasise that it has not always been possible to identify drone pilots and that "military installations, airports, but also other critical infrastructure, such as arms manufacturers or port facilities, are the most affected," which is why "we take this matter very seriously." In the interview, Muench also mentioned an increase in Russian espionage, sabotage, and disinformation activities. (ANSA).