Los Angeles Mayor Antonio Villaraigosa says one person has been killed in one of the two wildfires burning on the edges of the city.

The mayor says it may be some time before the victim can be identified.

Authorities have not released any of the circumstances of the death, which occurred Monday in a 3,700-acre blaze in the northeastern San Fernando Valley.

Los Angeles County Fire officials say gusting winds early Monday morning forced the fire to jump lines, spurring the closure of sections of the Foothill and Ronald Reagan Freeway and burning several structures.

Containment was scaled back from 20 percent to just 5 percent. Officials said the fire had burned 3,712 acres.

A large swath of houses was under mandatory evacuation.

Fire officials say swift winds are expected to continue throughout the day.

“This is what we feared the most,” said Los Angeles County fire Capt. Mark Savage. “The winds that were expected, they have arrived.”

Flames jumped the Foothill Freeway, which was closed in both directions for about a three-mile stretch in northern Los Angeles between the 118 Freeway and Interstate 5 amid the morning rush hour, officials said.

“That was quite a jump, that’s an eight-lane fire break,” said fire spokesman Paul Hartwell.

The eastbound side of the 118 was also closed.

Inspector Ron Haralson said the blaze had reached a mobile home park and an industrial area.

Fire officials could not say how many structures had burned, but said the park had been evacuated earlier Monday before flames reached it.

There were no reports of any injuries.

Savage said the blaze had jumped a fireline at about 4:30 a.m. in an area of Lopez Canyon in the eastern San Fernando Valley that had already been evacuated.

Winds in the area were gusting as high as 65 mph, Haralson said.

Water-dropping aircraft returned to the sky after sunrise. Television showed one helicopter attempting to drop water on a building, but the winds blew the water away long before it could reach the structure.

The blaze 20 miles north of downtown Los Angeles sent about 1,200 people from their homes.

Fire officials had warned during the night that the fire could be a “sleeping giant” as the region’s serious fire season began with the arrival of Santa Ana winds.

The fire had burned through 3,200 acres of rugged terrain in the Angeles National Forest. More than 1,200 people had evacuated.

The fire, which began early Sunday, was 20 percent contained early Monday. One home was destroyed Sunday.

A “fire weather watch” was declared through Tuesday for all of Southern California except the deserts.

Some 1,000 people were deployed to fight the fire.

The blaze forced the evacuation of about 450 homes in neighborhoods around Kagel and Lopez canyons. Many displaced residents sought refuge at a shelter set up at nearby San Fernando High School.

Most schools in the area were closed Monday.

The cause of the fire was under investigation.

Also Monday, Ventura County firefighters battled a 30-acre wildfire near a Santa Paula oil facility.

The fire was reported just before 4 a.m. and arriving firefighters found about 10 acres ablaze in a remote area about 70 miles northwest of Los Angeles.

No homes were threatened and there are were no evacuations, but structures at the oil facility were in danger.