Large swaths of Spain and Portugal plunged into darkness on Monday. 

Spanish power grid operator Red Electrica wrote on X:

• Plans activated to restore electricity supply in collaboration with sector companies following the blackout that occurred in the peninsular system.

• The causes are being analyzed, and all resources are being dedicated to resolving it.

"Parts of France also appear to be affected, according to Spanish media reports, which said Seville, Barcelona and Valencia were hit by the outage," SKY News reported.

Bloomberg's Javier Blas called the power outage "Massive -- really, massive." 

"Massive -- really, massive -- electricity outage hits Spain, which large part of the country suffering blackouts (including Madrid and Barcelona). Data from Spain's national grid shows a lost of >10 GW of demand, from ~26GW to ~12GW in a few seconds. Reason unknonw."

Cloudflare reported that internet connectivity dropped "by as much as 30% in Portugal and 37% in Spain" due to the power outages. 

Outages have begun to affect air travel. 

Footage:

Red Electrica provided no details about what caused the nationwide blackout. 

How long until Brussels blames the Russians? 

* Developing