US intelligence agencies estimate that the failed UAV attack on Leipzig-Halle Airport in Germany in August was linked to an alleged Russian sabotage campaign targeting European infrastructure. German officials reportedly considered invoking NATO's Article 5 of collective defense if the incident led to mass casualties. According to the report, the Kremlin then warned Berlin through a back channel that the incident would not be the last of its kind. The claims are based on intelligence assessments and sources cited by the newspaper. The report attributing the attack to Russia has not been independently determined in public.