A brush fire that started just south of San Diego-Riverside County line near Pala Temecula Road and consumed 320 acres of brush was nearly contained by late Saturday.

A state Division of Forestry spokeswoman said the fire started about 2:30 p.m. and moved northeast through an area where there are several structures. An unoccupied house and a shed were destroyed about 4 p.m. as the fire moved into Riverside County.

About 350 state and the U.S. Forest Service firefighters battled the blaze, which was believed to be an arson fire. Firefighters were aided by six aerial borate bombers and five bulldozers. The spokeswoman said the fire was 90% contained by 9 p.m.