Cuba’s power grid collapsed on Saturday leaving the country without electricity for a third time in March as the communist government battles with a decaying infrastructure and a US-imposed oil blockade.

The Cuban Electric Union, which reports to the Ministry of Energy and Mines, announced a total blackout across the island without initially giving a cause for the outage.

The union later said the blackout was caused by an unexpected failure of a generating unit at the Nuevitas thermoelectric plant in Camagüey province.

“From that moment, a cascading effect occurred in the machines that were online,” said a report from the Ministry of Energy and Mines, which activated “micro-islands” of generating units to provide power to vital centres, hospitals and water systems.

Authorities said they were working to restore power.

Power outages, whether nationwide or regional, have become relatively common in the past two years because of breakdowns in the ageing infrastructure. The breakdowns are compounded by daily blackouts of up to 12 hours caused by fuel shortages, which also destabilise the system.

The last nationwide blackout was on Monday. Saturday’s outage was the second in the past week and the third in March.

The blackouts severely disrupt daily life, reducing working hours, making it difficult for people to cook or refrigerate food, and forcing hospitals to cancel some surgical operations.

President Miguel Díaz-Canel has said the island has not received oil from foreign suppliers for three months. Cuba produces barely 40% of the fuel it needs to power its economy.

Cuba’s ageing grid has drastically eroded in recent years. But the government has also blamed the outages on a US energy blockade after Donald Trump in January warned of tariffs on any country that sells or provides oil to Cuba.

The Trump administration is demanding that Cuba release political prisoners and liberalise politics and the economy in return for lifting sanctions. Trump also has raised the possibility of a “friendly takeover of Cuba”.

Another reason Cuba has been struggling with dwindling oil is the removal of Venezuela’s leader, which halted critical petroleum shipments from the nation that had been a steadfast ally to Havana.

Trump has for months suggested Cuba’s government is on the verge of collapse. After a previous time Cuba’s electric grid collapsed, Trump told reporters he believed he’d soon have “the honour of taking Cuba”.