A brush fire that has burned approximately 400 acres in mountainous terrain in Jurupa Valley and prompted evacuation orders and warnings was 5% contained Saturday.

Firefighters responded at approximately 5:20 p.m. Friday near Pyrite Street and Granite Hill Drive to reports of a brush fire that initially consumed about 15 acres of vegetation, according to Cal Fire.

There were nearly 300 firefighters on the scene, including eight hand crews. They were aided by water drops from two helicopters, fire officials said.

Evacuation orders were issued for nearby areas, with warnings set in place north of Sierra Avenue, south of Lauren Lane, east of Sierra Avenue, and west of Armstrong Road as of 6:45 p.m.

A care and reception site has been established at Jurupa Valley High School. People under evacuation orders can bring their animals to the Western Riverside County/City Animal Shelter in Jurupa Valley.

The cause of the Pyrite Fire was under investigation, officials said.