Cuba's power-grid operator said it had restored electricity to most of the capital Havana on Monday even as Tropical Storm Oscar lashed the island's eastern end, downing trees and power lines.

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 has ground to a halt for a second time in as many days, leaving 10 million on the island without power and the Caribbean island in a growing sense of crisis.