A second-alarm pallet fire was burning in Monrovia Monday night, and a person of interest was taken into custody.

The fire was reported about 5:20 p.m. behind a commercial building at Huntington Drive and Mountain Avenue, near the Foothill (210) Freeway, according to the Los Angeles County Fire Department.

The blaze was quickly upgraded to a second-alarm response.

The public was advised to avoid the area of Huntington Drive and Mountain Avenue as firefighters worked to extinguish the flames.