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.

Tropical Storm Oscar doused Cuba on Monday, three days after a massive power failure plunged more than 10 million people into the dark as the island worked to restore its decades-old power grid.

Cuba's national grid collapsed on Friday, leaving the entire population of 10 million people without electricity and underscoring the precarious state of the Communist-run country's infrastructure and economy.