Los Angeles grid stabilised after widespread outage

The electricity system in Los Angeles has been stabilised and is returning to normal, said a spokesman for the Western Electricity Coordinating Council.

A widespread power outage hit Los Angeles today, knocking out electricity to thousands of customers, snarling traffic and stranding high-rise office workers in elevators or trains as officials scrambled to determine the cause.

Authorities declared a state of emergency shortly after the 12.35pm PDT (7.35am NZT) blackout, which struck a wide swath of the city in seemingly random patches.

The power failure jangled nerves in Los Angeles one day after a suspected Al Qaeda associate made threats against America's second-largest city in a videotape aired as the US marked the fourth anniversary of the Sept. 11 attacks.

Los Angeles officials and police chief William Bratton had said there was no credible evidence of any planned attacks.

Department of Homeland Security spokesman Russ Knocke said the authorities there were monitoring the situation but, "At this time there's no indication of a nexus to terrorism."

A spokeswoman for the Los Angeles Dept of Water and Power said several receiving substations, possibly in central Los Angeles area, may have tripped and caused the outage.

A WECC spokesman also confirmed that a transmission line tripped off-line at about the same time of the Los Angeles outage. It was unclear which event -the substations tripping off-line or the transmission line shutting down -led to the outage.

"The city is on a tactical alert and obviously traffic is going to be impacted," said Los Angeles Police spokesman Kevin Maiberger as lines of cars jammed the city's freeways.

Maiberger described a tactical alert as "what happens when the city goes into a state of emergency. Police officers will only be responding to calls where there is a threat to life."

There were no evacuations planned and no reports of injuries. Within about an hour of the initial blackout, power was restored to some of the affected areas.

Los Angeles International Airport reported losing power briefly but said back-up power had averted flight disruptions.

A Los Angeles Department of Water and Power spokeswoman said it was not immediately known how many homes or businesses lost electricity, but it was in the thousands.

Outages were reported across downtown Los Angeles, Koreatown, North Hollywood, Burbank and the San Fernando Valley.

Television stations showed confusion at major traffic intersections as motorists tried to navigate through stoplights that were out. Freeway traffic was jammed as stoplight outages caused backups onto exit ramps.

In the financial district of Los Angeles, office workers huddled in groups, many stranded outside their buildings as the outage struck during lunch, stalling elevators in high-rise office towers.

- REUTERS