Spain's investigation into the power outage that blacked out the entire Iberian Peninsula this week continued Thursday as top security officials met Wednesday.

The sweeping power outage that hit Spain and Portugal this week has raised questions about the electricity grid in a region not normally known for blackouts.

Red Eléctrica, Spain’s electricity grid operator, ruled out a cyberattack, human error or unusual weather. Experts say it could take weeks to determine the cause.