The collapse follows nationwide blackouts last year that plunged Cuba's frail power-generating system into disarray.

Pockets of Cuba's capital Havana saw the lights flicker back on though vast areas of the city and country continued without electricity on Sunday morning, after a nationwide grid collapse that knocked out power to 10 million people.

Cuba suffered a massive power outage Friday night affecting Havana and the country's provinces that left millions in the dark. Cuba's Ministry of Energy and Mines said at around 8:15 p.m. local time an outage at the Diezmero substation on the outskirts of Havana had caused "a significant loss of generation in western Cuba and,