An island-wide blackout plunged Cuba into darkness Monday as the country’s deepening energy crisis continues to strain its fragile power system. 

The outage affected roughly 10 million people before limited electricity service was restored in some areas. 

"A total disconnection of the National Electric Power System is occurring," Cuba’s state-run Electric Union said Monday morning. "The causes are being investigated."

Cuba has faced increasingly frequent power outages in recent years as the country struggles with chronic fuel shortages and deteriorating electrical grids. The crisis worsened when President Donald Trump imposed additional sanctions in January and threatened tariffs on countries that provide oil to the island. 

MILLIONS LOSE POWER ACROSS CUBA AS TRUMP SANCTIONS CONTINUE TO FUEL ONGOING ENERGY CRISIS

During Monday’s blackout, public transportation was largely halted, and officials said tens of thousands of surgeries were canceled nationwide, according to The Associated Press (AP).

Authorities later said one generating unit had resumed operations roughly two hours after the collapse. 

"Microsystems are already operational throughout the country, to ensure protection for vital services," the Electric Union said. 

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The energy minister said officials were working to restore power while accusing the U.S. of contributing to Cuba’s energy struggles. 

"Vital services continue to be protected, amidst this complex situation exacerbated by the energy blockade we face," Vicente de la O Levy said.

Cuban President Miguel Díaz-Canel also blamed U.S. policies, describing the energy blockade as a "genocidal" measure imposed by Washington. 

"While the U.S. tries to induce a social explosion through asphyxiation by blocking fuel access to #Cuba, the UNE mobilizes to reverse the SEN outage," Díaz-Canel said, referring to Cuba’s National Electric Power System. 

"What the electrical workers are doing in the midst of a genocidal energy blockade is heroic."

Cuba’s energy crisis intensified earlier this year after a U.S. military operation captured Venezuelan President Nicolás Maduro and halted Venezuelan oil exports, cutting off a key source of fuel for the island. 

While Cuba produces only about 40% of the fuel it needs, a Russian tanker delivered roughly 730,000 barrels of oil to the country in March, supplies that were depleted by the end of April, according to The AP.

To conserve fuel, the Cuban government has imposed scheduled power outages that have lasted more than 24 consecutive hours in some areas, the outlet said. 

A blackout in early March affected Cuba’s western provinces, while a separate outage in mid-March plunged the entire island into darkness.