About 140 children are being evacuated from a campground near Rancho Santa Margarita as a five-acre brushfire burns in the Cleveland National Forest near Ortega Highway.

The flames broke out in an old building this morning and spread to the surrounding brush in the area just east of Rancho Santa Margarita.

Fire crews from 20 engines are fighting the blaze, which has charred five acres.

Buses from the Capistrano Unified School District are being brought in to evacuate the children. Several other campers in the area have already left.

Aircraft and fire helicopters are also being brought in to fight the blaze as a Red Flag warning remains in effect for much of Southern California.