Cuban authorities said on Thursday that electricity is slowly coming back to end a blackout that hit two-thirds of the beleaguered nation and stemmed from a lack of fuel under US pressure.

The grid that failed on Wednesday and left Havana and much of the country without electricity has now been reconnected nationwide and people should gradually see the power come back on, the energy ministry said.

"As of 5.01 this morning the national electrical system is reconnected," the ministry said in a statement.

It said more generation units are being brought back on line so people will have power again.

The blackout stemmed from a breakdown beginning shortly after noon on Wednesday at the Antonio Guiteras power plant, the island's largest.

The utility company said this was the immediate trigger of the blackout but the underlying problem is "the weakness of the electrical grid due to a lack of fuel" to run generators that support the national grid.

Fuel is scarce because the United States is severely restricting oil shipments to Cuba.

Cuba's electricity generation system is in shambles. Daily power outages of up to 20 hours are the norm in parts of the island, which lacks the fuel needed to generate power.

The crisis in the country of 9.6 million people comes at a particularly tense time since the US ouster of Cuba's top ally, Nicolas Maduro of Venezuela, on January 3.

Maduro's administration supplied about half of Cuba's fuel.

After his capture, Washington imposed an oil embargo on arch-foe Cuba but later eased it amid warnings from other Caribbean countries that it could trigger an economic collapse and make everyday people suffer unduly.

Still, US President Donald Trump has maintained his blockade of sorts, and oil shipments from Caracas to Havana are in limbo. (AFP)



Edited by Cecil Wong