Power failed in Cuba's capital Sunday night, plunging most of the city and some of its suburbs into darkness. Other cities far from Havana also had outages, although for only brief spans.

There was no immediate word on what caused the blackout, which hit a little after 8 p.m. in the middle of the nightly news on state television and was still out more than an hour later.

State radio made no mention of the power failure, and calls to the power system's headquarters met busy signals. Officials in the national government said they were not able to offer an explanation.

The outage knocked power out in a 24-mile-wide (40-kilometer) stretch from Havana's western residential neighborhoods across the city's center and Old Havana district and on to suburbs on the other side of the bay. In Havana's Vedado entertainment and business district, the only buildings with visible light were tourist hotels and upscale apartment towers, which have backup generators.

Problems extended well beyond Havana's city limits. Outages that began at the same time as Havana's were reported as far away as Santiago, the nation's second-largest metropolis about 475 miles (740 kilometers) away at the other end of the island. The power in Santiago returned after only a few minutes, however.

Electricity was out for about 20 minutes in the central city of Ciego do Avila, and power also failed in a town near the popular Caribbean resort area of Varadero.

Big blackouts were common in Havana a decade ago, when Cuba was dealing with an energy crisis. Isolated outages still hit the city on occasion, but citywide blackouts have become rare for Havana's 2 million residents.