Cuba's electricity grid collapsed late on Sunday, the state-owned grid operator said, plunging the island of about 10 million people into darkness as blackouts become more frequent.
The outage follows three nationwide blackouts in July and comes as a US-imposed oil blockade further strains the island's aging energy infrastructure.
The Unión Eléctrica de Cuba gave no further details of the situation in its posts on X/Twitter and Facebook.
Pressure on the power system has mounted as Cuba struggles to secure fuel imports.
It lost a key source of fuel after an oil blockade imposed by US President Donald Trump, following Washington's January 3 ouster of Venezuelan President Nicolas Maduro.
Imports from Venezuela, Mexico halted with US pressure
Venezuela had long been Cuba's primary oil supplier, with imports from Mexico also halted amid increased US pressure.
The power crisis coincides with a cautious opening of Cuba's tightly controlled energy sector, driven by fuel shortages and severe US sanctions.
Havana recently authorized its first foreign-backed fuel import venture and allowed nearly 200 Cub