Power went down Monday afternoon in vast areas of Spain, crossing over into Portugal and France causing widespread outages in homes and businesses and bringing transportation infrastructure to a halt. The cause of the outage is currently unknown. Lisbon, Madrid, Seville, Barcelona, and Valencia are reportedly affected. The outage began at around 12:30PM CET.

Portuguese police are reporting that traffic lights are down across the country, according to Reuters, alongside the metro in Lisbon and Porto being shut down and trains not running. A statement from Portuguese national energy supplier E-Redes, seen by The New York Times, says that the interruption “was due to a problem in the European electricity grid,” with Spain and France also impacted “due to faults in very high voltage lines.” The Basque Coast and the Burgundy region were also affected by the outages, according to the energy supplier.

Red Eléctrica, Spain’s national electricity system operator, said it’s working with energy companies to restore power in regions that are affected by the outage. “We are beginning to recover power in the north and south of the peninsula, which is key to gradually addressing the electricity supply,” the company said in its most recent statement. France’s electricity transmission system operator also says that all power has now been restored to the Basque region.