Cuba’s energy ministry said the national electrical grid had suffered a total collapse on Monday. Energy Minister Vicente de la O Levy said officials were working to restore energy and that they’ve already activated emergency “microsystems” that power vital services. CNN reported.

By Tuesday, power was gradually restored on the island and authorities were still investigating the cause of the blackout. About a third of Havana’s electricity being restored, according to the capital’s utility company.

Cuba has experienced several nationwide blackouts over the past few years, as the country’s aging electricity infrastructure struggles to meet demand.

The country’s power crisis worsened this year after the US forced Cuba’s main suppliers to stop oil shipments. In March, it had at least two total blackouts within a week.

On Monday, Cuba’s President Miguel Díaz-Canel criticized the US for blocking fuel imports on X, claiming Washington is trying to induce “a social explosion through asphyxiation.”

The island’s energy crunch has strained essential services, including education, transportation and medicine. Fresh sanctions by the US have also further deteriorated the Cuban economy and prevented many tourists from visiting the island.