HAVANA, Cuba (CNN) -- Cubans are used to the mundane inconvenience of brief, localized power outages that regularly hit the country's aging electricity grid, but the large blackout that plunged the western part of the Caribbean island into darkness Sunday night was unusual.
More than 2 million residents of the capital, Havana, lost electricity, except for those at hospitals and other places with generators, a government spokesman, who was not identified per government policy, said late Sunday.
Residents elsewhere in the socialist-ruled nation, including in Ciego de Avila in central Cuba, also said they didn't have any power, except for a few pockets of light.
By early Monday, power began to return to homes in Havana and elsewhere after several hours of outage.
The website of the state-run newspaper Trabajadores reported an outage on a 220,000-volt transmission line between Ciego de Avila and Santa Clara that affected service from Pinar del Rio -- the area on the western tip of the long, slender island -- as far east as Camaguey.
The brief report late Sunday said that the incident was under investigation and that workers were trying to restore power.
The streets of Havana lost electricity around 8 p.m. Residents of the capital took the outage in stride, congregating on the stoops of buildings in search of cooler air on a warm, humid night.
The dark streets were quiet early Monday, save for the hum of loud generators every few blocks.
Massive outages on this scale are rare in Cuba, unless a big storm passes over the island.
Weather reports for Havana indicated partly cloudy conditions on Sunday night with temperatures in the high 70s. Temperatures were forecast to hover around 90 degrees Fahrenheit on Monday.