Authorities were unable to explain the cause of the outage at least an hour after it occurred, though a possible cyberattack had not been ruled out and investigations were ongoing, officials said. The Spanish government urged residents to stay put to avoid traffic chaos. “The government is working to identify the origin of this incident and dedicating all possible resources to resolve it as quickly as possible,” Prime Minister Pedro Sanchez’s office said.

National grid operators in Spain and Portugal confirm that a massive electrical blackout has hit the Iberian Peninsula today, starting just a couple of minutes after 12:30 pm Central European Summer Time (10:30 am UTC, or about 6:30 am US Eastern Daylight Time). The outage appears to have resulted in near-total loss of electricity in Spain, Portugal, the Principality of Andorra, and at least some portions of southeast France.

Videos online show railway networks in Spanish cities plunged into chaos, with people being evacuated through tunnels as blackouts hit underground stations and halted trains. Parts of France also lost power after the outages in Spain and Portugal, the country's grid operator confirmed. Further outages have been reported as far as Belgium, according to the latest information.