“Hybrid and cyber-attacks can trigger Article 5,” Nato secretary-general Jens Stoltenberg said on Tuesday when asked about the act of sabotage on the German rail network at the weekend and the twin leaks at the Nord Stream pipelines. Stoltenberg refused to comment on specific events, as investigations are ongoing, but warned that hybrid and cyber-attacks “can constitute armed attack against a Nato ally”, triggering the joint defence action.