Air drops over a brush fire in San Bernardino County came to a temporary halt Sunday when firefighters encountered a recreational drone, fire officials said.
The so-called Mill 2 Fire broke out about 2:30 p.m. near Mill Creek Canyon and Bryant Street just north of Yucaipa, forcing the evacuation of four homes on the Yucaipa ridge, Cal Fire officials said.
As of 11:30 p.m., the blaze had charred 35 acres and was 10 percent contained.
Earlier, tanker operations were stopped when crews spotted the drone, but resumed a short time later, fire officials said.
"This could decrease the effectiveness of fire suppression operations, allowing the fire to grow larger and potentially threaten lives, property, and valuable natural and cultural resources," the U.S. Forest Service said in a statement.
The incident came less than a month after another drone grounded aircraft fighting a fire in the mountains east of Los Angeles.
The cause of Sunday's blaze was under investigation.
An Unmanned Aircraft System (drone) temporarily halted tanker operations on the #Mill2Fire, but operations soon resumed
— San Bernardino NF (@SanBernardinoNF) July 12, 2015