A massive power outage has knocked out electricity across parts of Spain and Portugal, shutting off traffic lights and causing chaos at airports, train stations and on the roads.

Several airports, including Madrid airport, which is Spain's busiest, had no electricity, El Mundo reported. Major cities including Barcelona, Seville and Valencia were without power. Parts of France were also affected by power loss.

The countries have a combined population of over 50 million people. It was not immediately clear how many people are affected.