Cuba experienced a nationwide blackout after its main energy plant failed, officials said.
Its power grid collapsed at around 11:00 (15:00 GMT), the energy ministry wrote on X.
Grid officials said they did not know how long it would take to restore power.
This follows months of lengthy blackouts on the island – prompting the prime minister to declare an “energy emergency” on Thursday.
Friday’s total blackout came after the Antonio Guiteras power plant in Matanzas – the largest on the island – went offline.
President Miguel Díaz-Canel Bermúdez said the situation was his “absolute priority”.
“There will be no rest until power is restored,” he wrote on X.
Earlier on Friday, officials announced that all schools and nonessential activities, including nightclubs, were to close until Monday.
Non-essential workers were urged to stay home to safeguard electricity supply, and non-vital government services were suspended.
Cubans have also been urged to switch off high-consumption appliances during peak hours, such as fridges and ovens, according to local media.
Prime Minister Manuel Marrero addressed the public in a televised message on Thursday, blaming deteriorating infrastructure, fuel shortages and rising demand for the electricity failures.
“The fuel shortage is the biggest factor,” he said.
The head of the National Electric Union (UNE) Alfredo López Valdés also acknowledged the island had been facing a challenging energy situation, with shortages chiefly to blame.
Extended blackouts – particularly one this widespread – are always a tense time in Cuba.
In part, because the ability to keep the lights on represents a potential public order issue for the Cuban Government.
In July 2021, thousands of protesters spilled into the streets in demonstrations sparked by days-long blackouts in much of the country.
The desperation caused by precious food stuffs going to waste in warm fridges and freezers was exacerbated by citizens going for days with no air-conditioning or ceiling fans in the island’s stifling heat.
In many buildings, electric pumps bring water to the taps, so no power also meant no water.
Furthermore, no petrol at the pumps mean that people can’t work or use their cars to solve basic problems or tend to urgent needs.
The Cuban Government has becoming increasingly aware that many on the island have lost a degree of fear over speaking out about the many daily problems they face on the island.
Some are even prepared to take to the streets and chant anti-government slogans, if conditions merit it.
In March, Hundreds of people in Cuba’s second-largest city, Santiago, staged a rare public protest over chronic power blackouts and food shortages.