Cuba is experiencing a nationwide blackout after its main energy plant failed, knocking out power to its 10 million people.

Its power grid collapsed at around 11:00 (15:00 GMT) on Friday, the energy ministry announced on social media.

Grid officials said they did not know how long it would take to restore power.

The island has suffered months of lengthy blackouts, 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.

The head of electricity supply at the energy ministry, Lazara Guerra, was later quoted by AFP news agency as saying the process of restoring power was in its early stages.

There was, she added, "some level of electricity generation" that would be used to start up power plants in several regions of the country.

Earlier on Friday, officials announced that all schools and non-essential 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 such as fridges and ovens during peak hours, according to local media.

"This is crazy," Eloy Fon, an 80-year-old pensioner living in central Havana, told AFP.

"It shows the fragility of our electricity system... We have no reserves, there is nothing to sustain the country, we are living day to day."

Bárbara López, 47, a digital content creator, said she had already "barely been able to work for two days".

"It's the worst I've seen in 47 years," she said. "They've really messed up now... We have no power or mobile data."

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 means that people can't work or use their cars to solve basic problems or tend to urgent needs.

The Cuban Government has become increasingly aware that many on the island have lost a degree of fear over speaking out about the many daily problems they face.

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.