Authorities in western Germany have issued warnings to approximately 10,000 residents in Mechernich to avoid using tap water due to potential sabotage at a water supply site connected to nearby military bases, including Bundeswehr and NATO facilities. The alarm was raised after a hole was discovered in the fence around a water storage site, leading to concerns of contamination. Initial tests have not shown chemical or biological contamination, but residents are still advised to boil water as a precaution. This incident follows similar suspicions at the Cologne-Wahn air force base and another NATO base in Geilenkirchen, both of which have heightened security due to abnormal water values and potential unauthorized entries. These events occur amid heightened concerns of sabotage linked to geopolitical tensions involving Russia's invasion of Ukraine.