A large-scale blackout struck western Cuba on Wednesday, leaving millions without power in the latest outage to hit the island as it grapples with dwindling oil supplies due to sanctions imposed by President Donald Trump.

The U.S. Embassy in Cuba said that at approximately 12:41 p.m., there was a "disconnection of the national electrical grid resulting in a complete power outage" stretching from Camagüey to Pinar del Río, including the greater Havana metropolitan area.

"Cuba’s national electrical grid is increasingly unstable and prolonged scheduled and unscheduled power outages are a daily occurrence across the country to include Havana," the embassy said. 

"Outages affect water supply, lighting, refrigeration, and communications. Take precautions by conserving fuel, water, food, and mobile phone charge, and be prepared for significant disruption."

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The incident was reportedly caused by an unexpected shutdown of the Antonio Guiteras thermoelectric plant, located roughly 62 miles east of Havana.

Local reports indicate the island may need at least three days to restore operations, according to the Associated Press.

Vicente de la O Levy, the minister of Energy and Mines of Cuba, added that "We are working on the restoration of the SEN amid a complex energy situation." 

At least one power plant, Felton 1, remains online, he said.

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Reuters reported that, because Cuba is accustomed to frequent power outages caused by state-imposed energy rationing, some traffic lights and businesses remained operational thanks to solar panels or backup generators. Many residents have also installed solar panels on their homes and vehicles to maintain electricity amid soaring fuel prices, the outlet said.

Cuba has endured a string of widespread blackouts in recent years due to long-standing issues with its aging power infrastructure and chronic fuel shortages.

However, the situation worsened in January after a U.S. military operation captured Venezuelan President Nicolás Maduro and halted Venezuelan oil exports, effectively choking off Cuba's key source of fuel.

Cuban President Miguel Díaz-Canel stated in January that, despite the U.S. severing Havana’s energy lifeline, his administration would not negotiate with Washington to establish a new agreement.

Reuters contributed to this report.