A widespread power outage struck western Cuba on Wednesday, leaving millions of residents from Havana to central regions without electricity in the latest disruption to affect the island's struggling electrical grid.

The blackout affected areas from Pinar del Rio in the west to Camaguey in central Cuba, according to Cuba's Electric Union. By Thursday, crews were working around the clock to repair a broken boiler at one of the country's largest thermoelectric plants, though officials warned that full power restoration could take three to four days.

State media reported that approximately 297,000 customers in Havana, representing 34% of the capital, had power restored by Thursday, along with 37 hospitals and five water supply stations. The electrical system was operating at limited capacity, with authorities prioritizing essential services including healthcare facilities and water supply infrastructure.

Cuba's energy crisis has deepened in recent months due to aging infrastructure and fuel supply challenges. Two power plants remained offline due to petroleum shortages, while some thermoelectric facilities have operated for over 30 years with minimal maintenance. The situation worsened after key oil shipments from Venezuela were halted following increased U.S. pressure on the South American country in January.

This marks the second major outage to hit western Cuba in three months, following a nearly 12-hour blackout in December caused by transmission line faults. Cuban officials have cited U.S. sanctions as preventing the purchase of new equipment and specialized parts needed for grid maintenance and modernization.

The U.S. Embassy advised Americans in Cuba to prepare for significant disruptions and conserve essential supplies including fuel, water, food, and mobile phone batteries during the ongoing power restoration efforts.