Cuba made fast progress restoring power to swaths of the Caribbean island nation on Tuesday, both in Havana and outlying provinces, even as emergency and grid workers struggled to reach areas ravaged by Tropical Storm Oscar.

Cuba's power-grid operator said it had restored electricity to parts of Havana on Monday following multiple grid collapses over the past four days, while Tropical Storm Oscar lashed the island's eastern end.

By Monday afternoon, around 89 percent of customers in the capital had power again, however many residents outside Havana remained without electricity, according to the authorities.