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Private drones hampered firefighters battling a raging wildfire in California Friday that swept over an interstate and torched 20 vehicles, fire officials said.

Five drones were flying over the wildfire dubbed the North Fire Friday, and their presence caused firefighting aircraft to leave the area for about 20 minutes, the California Department of Forestry and Fire Protection said Saturday.

"We do believe that this affects our firefighting operations. It was very windy yesterday, and any time air operations are halted that affects our ability to put out these fires," Janet Upton, a spokeswoman for the department, said in a statement to NBC News.

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Three of the five drones left the area right away, but two drones interfered with firefighting operations, U.S. Forest Service spokesman John Miller said.

"Two of the drones pursued our lead plane. One underneath, one actually flying over the top," Miller told NBC's Gadi Schwartz.

"This was an immediate threat to the safety of those firefighters in the air. It could kill them," he said. "So the air attack made the decision immediately to call off the lead plane and the helicopters and they headed to the east and went into an orbit."

Burned terrain is seen on the reopened southbound side of Interstate 15, the main connector between Southern California and Las Vegas in the Cajon Pass, Calif., on Saturday, a day after the North Fire swept through and burned cars on the freeway. Matt Hartman / AP

The fire began near the Interstate 15, the main highway between Los Angeles and Las Vegas, at around 2:30 p.m. Friday but was fueled by hot winds gusting at 40 mph and quickly grew, officials said. Eighteen vehicles and two big rigs were set ablaze and destroyed after the fast-moving fire jumped the freeway.

The Federal Aviation Administration said it was aware of the reports of drones operating in the area of the fire.

Rain and cooler temperatures provided a welcome relief Saturday as firefighters continued to battle the fire in San Bernardino County, which remained at 3,500 acres and was 45 percent contained, the U.S. Forest Service said. The fire threatens up to up to 700 structures in the Baldy Mesa area.

"Things look so much better," Bob Poole, a U.S. Forest Service spokesman, told The Associated Press Saturday as he looked across the charred landscape dotted with a half-dozen small plumes of smoke.

California is in the fourth year of a historic drought, exacerbating wildfire conditions.