A mountain lion has attacked a dog that tried to defend its owners on a trail in the Santa Ana Mountains.

Orange County sheriff's Lt. Lloyd Downing says the dog was severely mauled Tuesday near a campground in the Cleveland National Forest.

Officials say two people were hiking with their dog when a 100-pound mountain lion approached. The dog, a shepherd mix, tried to defend its masters and was injured in the stomach.

Downing says the man waved his arms and screamed until the lion broke free of the dog, which was taken to an animal hospital. The dog's condition was not immediately clear.

Sheriff's deputies and Forest Service officials have not located the mountain lion.