Cuba’s electrical grid went offline Friday after one of the island’s major power plants failed, the energy ministry said.  

The massive outage left millions of Cubans without power and prompted the government to implement emergency measures to slash demand, including suspending classes, shutting down some state-owned workplaces and canceling nonessential services.

The government announced that one of the nation’s main thermoelectric plants, La Antonio Guiteras, had ceased operations at about 11 a.m. local time, with authorities saying it was only offline temporarily.  

Cuban officials said that the blackout, which started late Thursday, saw 1.64 gigawatts go offline during peak hours in the early evening, about half the total demand at the time.

The government was still working to restore service by Friday afternoon. “From the highest levels of the state we are working to solve this energy contingency as soon as possible,” Prime Minister Manuel Marrero posted on social media. “We will not rest until service is restored.” 

Earlier in the day, Marrero said in a special address on national television that the government had been “halting economic activities to ensure energy for the population.”

During his address, Marrero was accompanied by Alfredo López, chief of the state-owned utility, UNE, who said the outage stemmed from increased demand from small- and medium-sized companies and residences’ air conditioners, as well as breakdowns in old thermoelectric plants that haven’t been properly maintained, and a lack of fuel to operate some facilities.

The Energy Ministry posted on social media around 4 p.m. Eastern Time that it was still reviewing all thermoelectric plants, fuel availability and the state of the power grid. 

“There is not a defined timeline for total power restoration, but we are working to reconnect the electric system as soon as possible,” a ministry official said in a video posted on social media.

Changes to electricity rates for small- and medium-sized companies, which have proliferated since they were first authorized by the communist government in 2021, are also being considered, Marrero said.

Marrero sought to placate people’s concerns about the outage, citing an expected influx of fuel supply from Cuba’s state-owned oil company.

Even in a country accustomed to frequent outages amid a deepening economic crisis, the size of Thursday night’s blackout left millions of Cubans on edge. Residents shut their doors and windows, which they typically leave open at night, and candles or lanterns were visible inside homes.

Donald Trump, who turned 78 in June, would be the oldest person in U.S. history to be elected president if he wins in November. The question of age and fitness for office has flared repeatedly this political season, including on Tuesday when one interviewer asked Trump whether he would appoint a CEO his own age.

Perhaps not surprisingly, Trump said he would although with some caveats, noting that he wouldn’t hire his former presidential rival, President Joe Biden, 81.

“I know many people in their 80s. I know guys in their 80s that won’t leave the company, like family companies where they don’t want the kids to take over because they’re much more competent than their kids,” Trump told his interviewer, Bloomberg editor-in-chief John Micklethwait, at the Economic Club of Chicago on Tuesday. 

But there are few CEOs of large U.S. companies who are as old or older than Trump. Among Fortune 500 companies — the 500 largest U.S. companies based on their total revenue — there are only six who are older than the former president, according to financial firm Madison Trust. They are:

• Warren Buffett, CEO of Berkshire Hathaway, 94
• Roger Penske, CEO of Penske Automotive, 87
• Robert Greenberg, CEO of Skechers, about 83
• Albert Nahmad, CEO of Watsco, 84
• Seifi Ghasemi, CEO of Air Products, about 80
• A.J. Teague, CEO of Enterprise Products, about 79

Most CEOs of publicly traded companies are in their 50s, representing about half of all chief executives, according to a January analysis by The Conference Board. Only about 14% of CEOs are over 60 years old, the group found.

“You just say some of our great world leaders are in the 80s,” Trump said. “And if you look throughout history, some of our greatest world leaders were in their 80s. No, that wouldn’t bother me.”

Trump has so far refused to disclose new details about his physical or mental well-being, breaking decades of precedent. His rival, Vice President Kamala Harris, released her records earlier this month, with her physician declaring she is in “excellent health” and “possesses the physical and mental resiliency” required to serve as president.

Although there’s no requirement that candidates release their health data, presidential nominees traditionally disclose medical records voluntarily given the demands of the job, particularly if there are concerns about their age.

Meanwhile, more Americans than ever are working past the age of 75, representing one of the fastest-growing groups of workers. In 2022, about 1 in 12 people older than 75 was still in the workforce, up from 1 in 20 about two decades earlier, according to data from the Labor Department.

Some workers over 75 are staying in the workforce because they enjoy their jobs and can’t envision retiring. But many continue working because they can’t afford to retire, something that’s not an issue for Trump, who is worth an estimated $5.6 billion.

contributed to this report.