A wildfire that has been raging in Eastern Arizona since late last month continued its relentless advance on Wednesday, amid rolling power outages and reports of gasoline shortages, authorities said.

Fire crews fighting the mammoth Wallow Fire face another day of winds and low humidity, a day after the blaze forced the evacuation of a major part of Eagar community, firefighters said.

Electricity began cutting on and off in the White Mountain town and nearby Springerville Tuesday evening as officials tested the power grid, which they fear could be threatened by the flames, according to The Arizona Republic newspaper.

Gasoline supplies, meanwhile, were reportedly running low.

More than 1,000 people were evacuated from Eagar by the end of Tuesday, and they joined about 2,600 people forced to leave their homes in Greer, Alpine, Nutrioso and other mountain communities in recent days, authorities said.

The fire was growing by the hour, leaping farther north and has now consumed about 389,000 acres (about 157,545 hectares) with at least 11 structures burned and 588 more threatened by the flames, the report said.

So far there has no report of injuries.

Authorities would meet with residents of the towns most affected and discuss what structures have been lost, said the report.

Governor Jan Brewer has declared a state of emergency in two counties most affected by the fire, and transportation officials have closed about 240 kilometers of highways.

The Wallow Fire is now the second-largest in Arizona history, and at zero percent containment, it has become the No. 1 firefighting priority in the nation.

The fire, which started May 29, was believed to be caused by a campfire.

The region's steep, pine-dotted terrain and flame-fanning weather have thwarted a counterattack by 2,100 firefighters, 20 helicopters and eight bulldozers.

"The fire moves so fast. It's the same as holding a matchstick upside down," said Jim Hyland, a spokesman for the firefighting operation, which has drawn crews from around the country.

The National Weather Service issued a red flag warning for Wednesday, which means that high winds gusting to 35 mph and low relative humidity will prevail. They also predict winds gusting from 22 mph up to 38 mph for the Wallow Fire area for next three days and temperatures hovering around 80 degrees Fahrenheit.