The announcement came as the country’s top criminal court announced a probe into possible “sabotage” of critical infrastructure.
Sanchez refused to rule out potential explanations, and defended his government’s planned nuclear phase-out.
“All the necessary measures will be taken to ensure that this does not happen again,” Sanchez told a press conference a day after Spain and Portugal were plunged into darkness, cutting phone and internet access and stranding trains.
In its separate announcement, the top criminal court, the Audiencia Nacional, said it was investigating whether the blackout was “an act of computer sabotage on critical infrastructure” that could be classified as “a terrorism offence”.
Its announcement came after Spanish grid operator Red Electrica ruled out a cyberattack as the cause of the crisis.
Spain’s far-right Vox party attacked the leftist government by linking the sudden loss of power to the scheduled phase-out of Spanish nuclear plants, prompting Sanchez to bite back.
“Those who link this incident to the lack of nuclear power are frankly lying or demonstrating their ignorance,” Sanchez said, saying atomic power “was no more resilient” than other electricity sources.
Sanchez said the nuclear plants were still being reconnected on Tuesday, which showed that, “with a greater dependence on nuclear, the recovery would not have been so quick”.
Renewable energies like solar and wind power are now leading the country’s energy mix and reducing nuclear’s contribution, raising hackles among some sector figures and the right-wing opposition. (AFP)