Almost all of Oahu had electrical power restored Saturday after a power failure blacked out the island's population of about 900,000 and thousands of holiday visitors, including President-elect Barack Obama.

Residents had been urged to just stay home after the lights went out during a thunderstorm Friday evening. Hawaiian Electric Co. was investigating the cause.

The utility had restored power to all but a few thousand of its 293,000 customers by early Saturday evening, said company spokesman Darren Pai.

Obama, wife Michelle, and daughters Malia and Sasha are staying in a $9 million, five-bedroom oceanfront home near downtown Honolulu. Power was restored to the neighborhood before 6 a.m.

Honolulu Mayor Mufi Hannemann told The Associated Press that while he did not talk with Obama directly, he conveyed an offer for assistance shortly after the blackout began and was told the president-elect and his family were doing fine.

"He replied he didn't need anything, was grateful for our offer and was going to put his family to bed," Hannemann said.

Hannemann said three generators had been installed earlier for Obama's rented compound. A fourth generator that Hawaiian Electric had sent for Obama was turned away, he said, but the power company later set up a bigger one in the neighborhood in case it was needed.

It was the first time all of Oahu lost power since Oct. 15, 2006, when a magnitude-6.7 earthquake shook the Hawaiian Islands and darkened Oahu and parts of other islands for up to two days. Authorities at the time expressed concern that the whole island lost power and the same concerns were being raised Saturday.

"This is something in Hawaiian Electric's hands," said Hannemann, who governs the entire island. "There are some legitimate questions to be raised. We would like to know how we can ensure this type of thing doesn't happen again."

Honolulu International Airport, handling thousands of tourists during one of its busiest weekends of the year, operated on emergency generators, with flights delayed up to several hours. Some incoming passengers were kept on planes for long periods.

Hospitals accepted only real emergencies and managed to stay open, shutting down visiting hours early, Hanneman said. Only sporadic calls came in with minor traffic accidents and people stuck in elevators, and "there was nothing extreme or chaotic," Hannemann said.

Parking lots at malls were jammed with shoppers trying to get out when stores had to close early on one of the busiest shopping days of the year.

Hawaiian Electric spokesman Peter Rosegg said the initial power failure hit at 6:45 p.m., affecting most of the island. The rest of Oahu lost power two hours later when the last generator failed.

The telephone provider Hawaiian Telcom kept most of its system in service on generator and battery backup, spokeswoman Ann Nishida said.

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