CUBA’S power grid collapsed Saturday, leaving the country without electricity for a third time in March.

This comes as the island’s government battles with a decaying infrastructure and a deepening of the illegal economic blockade imposed by the United States.

The Cuban Electric Union said the blackout was caused by an unexpected failure of a generating unit at the Nuevitas thermoelectric plant in Camaguey 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.

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

The already harsh situation in Cuba, caused by decades of an illegal US blockade of the island, which was recently deepened after Washington carried out an illegal attack on Venezuela on January 3, killed 100 people and kidnapped President Nicolas Maduro and first lady Celia Flores.

Washington then stopped all Venezuelan oil supplies to Cuba and threatened heavy tariffs against any country that supplied fuel to the Cubans.

The blackouts have caused major disruption in Cuba.

This includes disruptions to working hours, transport, food storage, cooking and the delivery of public services. There are multiple examples of where hospitals have been forced to cancel surgeries.

President Miguel Diaz-Canel has said the island has not received oil from foreign suppliers for three months.

Activists from around the world have arrived in Cuba with humanitarian assistance.

The Our America convoy was welcomed at a ceremony in Havana on Saturday by President Diaz-Canel.

He said: “The courage of these friends of all ages, willing to share in our challenges during such a difficult time for the country, is truly touching.”

He described the act as a “beautiful lesson of dignity and humanity that heroic Cuba appreciates and will never forget.”

The group of more than 600 peace activists from 38 nations delivered a significant donation of food, medicine and other essential supplies.

Organisers of the convoy, which includes Progressive International, have disclosed plans to transport over 20 tons of humanitarian aid to Cuba through various routes over the coming days, by air, land and sea.

The initiative has attracted international figures, including former Podemos leader Pablo Iglesias and veteran British parliamentarian Jeremy Corbyn.