SAN DIEGO, Calif. -

A wildfire that scorched about 150 open acres in a rugged area near Boulevard at the U.S.-Mexico line was 80 percent surrounded this afternoon and was expected to be fully contained Friday night.

The so-called Border Fire crossed into southeastern San Diego County late Thursday morning after charring roughly 600 acres in the northern reaches of Baja California since the previous day, according to Cal Fire.

At least one crew member with the state agency was injured while battling the flames, suffering mild heat exhaustion, said Cal Fire Capt. Mike Mohler.

The blaze posed no danger to inhabited areas on the U.S. side of the border. It was unclear if it threatened or damaged any structures in Mexico.

Cal Fire sent eight ground teams, four air tankers and three helicopters  to beat back the flames. Assisting in the effort were personnel from Heartland Fire & Rescue, the San Diego County Sheriff's Department, the U.S. Border Patrol, U.S. Department of the Interior's Bureau of Land Management and Forest Service.

The crews were able to halt the fire's spread at about 15 acres by mid-afternoon Thursday, but unexpected wind gusts caused flames to cross the containment lines in the early evening, Cal Fire spokeswoman Roxanne Provaznik said.