HAVANA (AP) — An islandwide blackout struck Cuba on Friday for the second time this week as the nation of nearly 10 million people grapples with a crumbling power grid and fuel shortages stemming from a U.S. energy blockade.

While total blackouts have become increasingly common in the Caribbean country, it’s unusual for back-to-back ones to hit just days apart. Cuba’s Electric Union confirmed the outage on X.

Authorities in Cuba said the cause of the blackout was a “fluctuation in the parameters” following a failure in a line connecting the provinces of Santa Clara and Sancti Spíritus.

The electrical grid in Cuba is particularly fragile, both due to the lack of maintenance of its aging infrastructure — some power plants are over 30 years old — and the scarcity of the fuels on which it depends.

“It has been another very difficult week under the impact of the energy blockade: two disconnections of the National Electric System (SEN), almost no fuel to power the plants, and several units out of service,” Prime Minister Manuel Marrero said on his social media account.

Authorities reported that they have already begun restoring power to some areas.

On Monday, another massive blackout affected nearly 10 million people nationwide. Authorities reported during the week that service was gradually being restored from that outage.

Friday’s national collapse of the electricity system is the fourth so far this year. A blackout in mid-May affected the island’s eastern provinces, while a blackout in mid-March struck the entire island.

Fuel has been running out across Cuba since January, when U.S. President Donald Trump threatened tariffs on any country that sells or provides oil to the island, deepening the island’s ongoing economic and financial crisis. Public transportation has largely been halted, and officials have canceled tens of thousands of surgeries.

Cuba produces only 40% of the fuel it needs, while the 730,000 barrels of oil delivered by a Russian tanker in late March ran out by the end of April. The government also has been rationing power with intentional outages that can stretch to more than 24 consecutive hours.

The Associated Press