Traffic on the 5 Freeway slowed Monday afternoon due to a brush fire burning in the Castaic area.

The small fire reported at about 2:30 p.m. was on a hillside covered in dry, brown brush near the 5 Freeway at Lake Hughes Road. At least one water-dropping helicopter was making runs on the fire as it climbed toward a neighborhood.

Details about how the fire started were not immediately available.

Northbound traffic backed up due to the flames.

Refresh page for updates on this developing story.