(TheBlaze/AP) -- Power failed in Cuba's capital Sunday night, plunging most of the city and some of its suburbs into darkness.
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.
State radio, however, made no mention of the power failure, and calls to the power system's headquarters gave busy signals.
Havana, Cuba is experiencing a blackout: more than 5 million people without lights, @marymurraynbc reports— NBC News (@NBCNews) September 10, 2012
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.
Big blackouts were common in Havana a decade ago, when Cuba had an energy crisis. Isolated outages still hit the city on occasion, but citywide blackouts have become rare.