A massive power outage has hit Spain and Portugal, causing widespread disruptions.



Authorities have been trying to restore their power grids since the mass outage started around noon on Monday.



According to the Reuters news agency and other media, train services were suspended, flights delayed, and traffic lights knocked out in many areas.



Footage taken in the Spanish capital of Madrid shows traffic jams forming as traffic lights stopped working. Lights at a metro station went off, leaving passengers in darkness.



Spain's nuclear safety council said the country's reactors are safe. Officials say, after some of the reactors stopped operating, emergency generators kicked in.



Spain declared a state of emergency after the massive power outage. Spanish Prime Minister Pedro Sanchez called on people to minimize travel and act calmly.



He said power is being restored to parts of the country, thanks to supplies from neighboring countries including France. He added that other steps that authorities are taking should allow Spain to restore power throughout the country soon.



Sanchez said there is so far no conclusive information on the cause of the blackout. He said his government is not ruling out any hypothesis.



Spanish media outlets reported that this was the worst power outage in Spanish history, given the scale of the impact and the size of affected areas.