European Commission chief Ursula von der Leyen on Tuesday said the leaks of the Nord Stream pipelines were caused by sabotage, and warned of the “strongest possible response” should active European energy infrastructure be attacked. “Spoke to (Danish Prime Minister Mette) Frederiksen on the sabotage action Nordstream,” von der Leyen said on Twitter, adding it was paramount now to investigate the incidents to get full clarity on the “events and why.” “Any deliberate disruption of active European energy infrastructure is unacceptable and will lead to the strongest possible response,” she warned.