Firefighters battling a blaze that already has scorched more than 6,400 acres were facing more hot, dry weather early Friday, but they expected to contain the wildfire by the weekend.

The fire, which has swept across a rural area east of Los Angeles, was 70 percent contained Thursday night, said Valerie MacAdam, a state Department of Forestry and Fire Protection (search) spokeswoman. Total containment was expected by Saturday night.

Meanwhile, a wildfire that started in Mexico jumped the U.S. border, officials said. It was about 30 percent contained. The cause of the 4,000-acre blaze was unknown.

Officials were aiming for full containment by Saturday evening after crews cut a 14-mile line by hand around the fire, said Matt Streck, a spokesman for the state forestry department.

A dozen American fire engines raced across the border around Thursday afternoon when winds shifted and a wall of flames bore down on the Mexican city of Tecate. Fire burned to a cinderblock wall at the edge of the city of 50,000, no structures burned.

"I really feel like we got the opportunity to save some lives," Streck said.

There was no threat to structures on the U.S. side of the border and evacuation orders in the area were lifted Thursday night.

A new wildfire broke out in Riverside County (search) on Thursday and quickly spread across 50 acres of steep hillside brush near Corona. Low winds helped firefighters, however.

"Firefighters were able to get a handle on this early on," said Capt. Jason Neuman of the California Department of Forestry and Fire Protection (search).