Cuba suffered a second nationwide blackout Saturday morning, hours after officials said power was being slowly restored.

“At 6:15 am a new total outage occurred of the national electroenergetic system,” a post on the Cuba Electrical Union’s official Telegram channel said. “The Electric Union is working to reestablish it.”

Previously Cuban officials said small pockets of power had been restored across the island although there were no immediate numbers provided of how many people had their service reconnected.

Some Cubans complained on social media that their power briefly returned before flickering out.

The blackouts threatened to plunge the communist-run nation into a deeper crisis, as without power people would also not have running water and refrigerated food would quickly begin to spoil.

Millions of people have been left without power over the last several days as the aging Cuban electrical grid repeatedly collapsed.

Saturday’s blackout follows an island-wide shutdown of Cuba’s electrical grid on Friday after one of the island’s major power plants failed, according to its energy ministry.

Cuban officials have blamed a confluence of events from increased US economic sanctions to disruptions caused by recent hurricanes and the impoverished state of the island’s infrastructure.

In a televised address on Thursday that was delayed by technical difficulties, Cuban Prime Minister Manuel Marrero Cruz said much of the country’s limited production was stopped to avoid leaving people completely without power.

“We have been paralyzing economic activity to generate (power) to the population,” he said.

The country’s health minister, José Angel Portal Miranda, said on X that the country’s health facilities were running on generators and that health workers continued to provide vital services.

In Havana, motorists on Friday tried to navigate a city where no street lights appeared to be working and only a handful of police were directing traffic. Generators are a luxury for most Cubans and only a few could be heard running in the city.

Classes at schools were canceled from Friday through the weekend, nightclubs and recreation centers were ordered closed, and only “indispensable workers” should show up at their jobs, according to a list of energy-saving measures published by the state-run website Cubadebate earlier on Friday.