In recent weeks, Germany has seen unidentified unmanned aerial vehicles (UAVs) flying over key strategic sites, including the US Ramstein Air Base, defense company Rheinmetall and chemical giant BASF, Der Spiegel magazine reports.

According to the publication, numerous drones were observed over the Ramstein base on the evening of December 3 and 4. Despite the measures taken, it was not possible to establish the identities of the operators of these devices. The American military confirmed the facts of suspicious flights, noting that they did not affect the personnel, objects or military equipment of the base.

Drones have also been spotted over Rheinmetall and BASF sites in recent weeks. The origin of these drones remains unknown and their appearance has raised concerns among German authorities.

The Flensburg prosecutor's office has opened an investigation into suspected espionage and sabotage. However, a spokeswoman for the German Defense Ministry declined to comment on the information provided to Der Spiegel.