The embassy added, "The electrical system remains vulnerable, and additional regular outages have been occurring more frequently and for longer periods. Scheduled power cuts occur daily, and unscheduled outages persist throughout Cuba."
Cuba’s energy ministry also posted about the power outage on social media.
The country’s power system has been struggling because of fuel shortages, the U.S.-imposed oil blockade and crumbling infrastructure.
Even when there isn’t a national outage, the country often endures rolling blackouts that leave millions without power.
The last national outage happened just last month, and Friday's marks the seventh this year.