GLENDORA, Calif. (CNS) — U.S. Forest Service firefighters have cleared a line of vegetation around 93% of a brush fire in the hills above Glendora and have prevented it from charring more vegetation, authorities said Monday.

“A total of 159 Angeles National Forest firefighters worked toward containment of the East Fire in the Angeles National Forest today,” Angeles National Forest officials said late Sunday. “The fire remains at 150 acres but with 93% containment.”

Officials said the East Fire is not threatening any structures or homes in the area.

Glendora Mountain Road, from Glendora to the East Fork Road, and Glendora Ridge Road, from Mount Baldy Road to Glendora Mountain Road, remained closed. East Fork Road from Highway 39 to Glendora Mountain Road was also closed. And San Gabriel Canyon was closed in the East Fork Day Use/East Fork Trail areas, officials said.

The cause of the fire remains unknown.

It was first reported at about 2:15 p.m. Thursday and was burning along Glendora Mountain Road and East Fork Road within the San Gabriel Mountains National Monument, according to the U.S. Forest Service.

Firefighters from Cal Fire, the U.S. Forest Service and the Los Angeles County Fire Department were originally dispatched to the Angeles National Forest to douse the flames.