MENIFEE, Calif. — Officials pledged to keep scouring a sun-scorched area of Southern California on Tuesday until they find an autistic 11-year-old boy who was last seen at his home during the weekend.

Temperatures have topped 100 degrees every day since Terry Dewayne Smith Jr. went missing, but that didn't stop hundreds of emergency workers and volunteers from combing the dry brown hills of Menifee on Tuesday.

Searchers are concentrating on a 55-square mile area, and there are no plans to stop the search.

"We pledge that we will continue this search effort until such time as circumstances dictate otherwise. We will continue searching, we will find Terry," said Scott Mann, mayor of Menifee.

The Riverside County Sheriff's Department and numerous other agencies, including the FBI, aided in the investigation and search of the region about 70 miles southeast of Los Angeles with the help of bloodhounds, helicopters and horseback riders.

Fear for the boy's safety was heightened because he might not be carrying any food, water or his medication.

The 4-foot-8 boy with sandy brown hair and brown eyes was last seen Saturday night, wearing blue basketball shorts. Local children were asked to not wear blue, to help avoid confusion.

Terry was last seen when he followed his 16-year-old half-brother, who told the boy to go home, the Desert Sun reported (http://mydesert.co/13Ki1X9 ). The boy's mother didn't realize he was missing until the next day.

Terry's mother shared details of the boy's habits on a Facebook page where the volunteer search was being organized. Without his medication, Terry may be "over sensitive and may be walking on his tiptoes," the page said.

Searchers were also instructed to call him by his nickname "Juju" because hearing his full name called out may cause him to believe he's in trouble and flee.

Temperatures in Menifee have consistently topped 100 degrees since Terry went missing, with the mercury reaching 108 degrees Monday.

Terry's aunt, Tracy Armato, told KCAL-TV that searchers should "be gentle. We don't know if he'll be scared of all the searchers."