As at least three major wildfires rage across the American southwest, the people tasked with controlling them are contending with an unusual problem beyond the flames themselves: Drones.

Officials say that small personal drones are increasingly being spotted flying near or above wildfires, interfering with aircraft used for aerial firefighting and firefighter transport operations. Small drones operating near wildfires put those aircraft at risk of collision. It’s unclear why people are flying drones near wildfires, but it’s likely they’re being used to record video footage of the blazes.

Firefighters spotted two drones in their air crew’s operating area on Wednesday in Arizona, the Arizona Republic reports. A drone almost collided with a fire crew’s helicopter in Utah the same week.

Over the weekend, airborne firefighters in California had to stall their operations when they spotted drones in the area while fighting the San Gabriel Complex fire. The U.S. Forest Service issued a warning in response, saying that flight restrictions were in effect and reminding the public that drone operators interfering with fire crews could be fined or jailed, according to The Los Angeles Times.

U.S. Forest Service spokeswoman Jennifer Jones told the Republic that drone activity over firefighting areas is becoming more frequent, reaching 21 reported cases last year and 9 so far this year. Three of this year’s drone incidents resulted in air crews returning to the ground, delaying the operations. “There’s no centralized method for tracking incidents, but we started to notice the trend of seeing UAVs over fire suppression operations in 2014,” Jones told the Republic.

Some drone advocates say they can be used to assist first responders in their efforts, but only when deployed with the acknowledgment and cooperation of authorities. Federal aviation officials recently approved a rule that opens the door for further use of drones in commercial applications, a move that may result in more drone firms offering their services to firefighters, search teams and so on.

[Arizona Republic]

The Leadership Brief. Conversations with the most influential leaders in business and tech. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Write to Julia Zorthian at julia.zorthian@time.com.