Cuba’s power grid failed Friday night, leaving millions of the island nation’s 10 million residents in the dark.

The outage, which began around 8 p.m. Eastern time, affected most of western Cuba, including the capital of Havana.

Cuba has struggled with blackouts in recent months, including a nationwide one in December. Friday’s power failure was the fourth widespread one in five months. Government officials blame U.S. economic sanctions for the ongoing crisis, while others point to aging infrastructure, fuel shortages and the island’s susceptibility to hurricanes.

Vicente de la O Levy, Cuba's minister of energy and mines, said on X Friday night that the country was making progress in restoring electricity. He gave no reason for the power grid’s crash apart from saying it started at the Diezmero substation, which then caused the National Electric System to fail.

Power was still out early Saturday morning; officials gave no estimation of when it would be restored.

CNN showed footage from Havana showing the city in darkness and pedestrians walking with flashlights.

In October, a dayslong power outage forced some in Havana to resort to cooking over improvised stoves in the street. The situation also spurred protests, a rarity in the communist nation. Protesters blocked streets with heaps of trash before security forces dispersed them.

At the time, O Levy dismissed the protests as "isolated and minimal incidents."