Spanish Prime Minister Pedro Sanchez warned of a “long night ahead,” as the worst blackout to hit Europe in over a decade approached the 12-hour mark with no cause clearly identified and an uncertain timeline for the full restoration of power.

Befuddled passers-by holding torches and mobile phones squinted through pitch-black streets early on Tuesday and stranded travellers spent the night at train stations after a crippling backout plunged Spain into darkness.

A blackout brought much of Spain and Portugal to a standstill on Monday, stopping trains, cutting phone service and shutting down traffic lights and ATMs for millions of people across the Iberian Peninsula.