The Federal Aviation Administration on Monday said it was investigating a second incident involving a drone illegally flying into North Bay fire areas, a day after police cited a drone operator for causing firefighters to briefly stop flying in and out of the Petaluma airport.

The FAA also added a new area with temporary flight restrictions around Napa, extending previous no-fly zones instituted last week around Santa Rosa and Sonoma.

FAA spokesman Ian Gregor said the second, previously unreported incident took place in Santa Rosa early last week. The clashes with drones come as the growing popularity of the consumer-flown devices has increased the number of drone sightings by aircraft pilots in the Bay Area.