Millions of people in Cuba remained without power Saturday after a failure of the nation’s electric grid left the island in the dark the previous night.

An outage at the Diezmero substation on the outskirts of Havana had caused “a significant loss of generation in western Cuba and, with it, the failure of the National Electric System.”

Cuba’s power grid collapsed Friday night, triggering a nationwide power outage and plunging its more than 10 million people into darkness.