A brush fire erupted Thursday on the north end of Anza, at the foot of the San Bernardino National Forest, scorching about five acres before crews reached the remote location.
The non-injury blaze was reported at 12:12 p.m. in the area of Howard and Old Ranch roads, two miles north of Highway 371, according to the Riverside County Fire Department.
The agency said that multiple engine and hand crews from the county, along with U.S. Forest Service personnel, were sent to the location and encountered flames moving at a moderate rate to the north with three to four structures threatened.
It was unclear whether they were outbuildings or residences.
Three Cal Fire air tankers and a water-dropping helicopter were summoned to make runs on the brusher, but as of 12:35 p.m., they had not initiated operations.
There was no immediate word on what might have triggered the blaze.