Cuba’s capital Havana plunged into darkness for a second night on Saturday as efforts to restore power proceeded in fits and starts, with setbacks slowing progress and leaving several million still without electricity across the island.

Cuba’s grid collapsed on Friday evening after a transmission line at a substation in Havana shorted, beginning a chain reaction that completely shut down power generation across the island, officials said.

The grid operator focused early efforts on ensuring electricity for vital services including hospitals, water supply and food production centers.

But by early Saturday night, neither of Cuba’s two largest power plants - Felton, in Holguin province, and Antonio Guiteras, in Matanzas - was generating electricity, leaving the majority of the island’s homes in the dark.

Lazaro Guerra, the country’s top electricity official, said on the evening newscast he hoped both power plants would come online overnight, but warned progress would be necessarily slow to avoid further setbacks.

The island’s two largest cities, Havana, in the west, and Santiago de Cuba, in the east, both saw efforts to restore power falter during the day on Saturday, forcing the grid operator to begin again from scratch.

The latest islandwide grid collapse in Cuba follows a string of nationwide blackouts late last year that plunged the country’s frail power generating system into near-total disarray, stressed by fuel shortages, natural disaster and economic crises.

Most Cubans outside Havana have already been living for months with rolling blackouts that peaked at 20 hours a day in recent weeks.

In Havana, a handful of hotels used generators to keep the lights on late on Saturday for tourists. But street and stop lights on even major boulevards were blacked out, residential areas were largely dark and most restaurants and bars were closed.

The country’s transportation ministry said bus travel, as well as flights in and out of the country’s various airports, continued unfettered by the grid collapse.

But severe shortages of food, medicine, fuel and water, combined with mounting hours of daily blackouts, have made life increasingly unbearable for many Cubans.

“It’s very complicated because without electricity, keeping food is difficult,” said Lazaro Hernandez, a cafeteria worker in Havana who was scouring his neighborhood for ice to help keep stores of ham and cheese cool overnight.

“We’ve been without power for hours now; we don’t know how much longer it will last.”

Cuba blames its economic woes on a Cold War-era US trade embargo, a web of laws and regulations that complicate financial transactions and the acquisition of essentials like fuel and spare parts.

US President Donald Trump recently tightened sanctions on the island’s communist-run government, vowing to restore a “tough” policy toward the long-time US foe.

Cuba, with the help of China, has invested heavily in the past year in developing large, state-run solar farms it says will help alleviate dependence on pricey and hard-to-source fossil fuels.

Many Cubans, like Victor Raul Bracho, a Havana musician practicing for a recording session on Saturday, carried on as normal despite the blackout.

“It’s not like we’re getting used to these problems, but we have to get on with our lives.”