A fire has broken out at the border of Los Angeles and Ventura counties and is spreading rapidly, threatening numerous hillside homes in the Calabasas and Hidden Hills areas.

UPDATE Jan. 9, 8:35 p.m. The Kenneth Fire that erupted Thursday afternoon on the border between Los Angeles and Ventura counties is reportedly being investigated as an arson case, with one person in custody. As of Thursday evening, the blaze has expanded to 960 acres, with no containment.

Firefighters raced to contain a new wildfire that erupted near homes in the area of Calabasas and West Hills, northwest of Los Angeles, on Thursday afternoon. The Kenneth Fire has burned more than 900 acres and is 0% contained.