Cuba reconnected its national electrical grid and restored power to the majority of the capital Havana by late on Sunday, energy officials said, nearly two days after an island-wide outage knocked out power to 10 million people.

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.

Millions of people in Cuba remained without power Saturday after a failure of the nation's electric grid left the island in the dark the previous night. The blackout is the fourth in the last six months as a severe economic crisis plagues the Caribbean country.