The blaze was about 25 percent contained on Saturday night, Melton said, and more firefighters were expected to work through the night to contain the blaze.
Elsewhere, firefighters on Saturday completed containment lines around a blaze that had scorched 1,680 acres west of Utah Lake.
Interagency Fire Center spokeswoman Kim Osborn said about 100 firefighters had completed containment by 8 p.m.
Efforts to snuff the AR Wildfire, which was sparked Thursday by target shooters, had been made difficult by hot weather and the tinder-dry condition of grass, brush, juniper and pinyon in rugged terrain where the fire was burning on and adjacent to Lake Mountain, roughly midway between Saratoga Springs and Eagle Mountain in Utah County. No injuries had been reported, and no structural damage had occurred.
On Friday, the Utah County Sheriff's Office had closed an area stretching from just south of Utah Lake's Pelican Point to north of Clyde Knoll. Those restrictions remained in place on Saturday.
Elsewhere, a hot weekend forecast along with thunderstorms and possibly lightning expected to periodically roll into the region prompted the Bureau of Land Management, state and national forests to impose fire restrictions in southwestern Utah's Washington County and the nearby Arizona Strip portions of Coconino and Mohave counties. Restrictions also include all Bureau of Indian Affairs-administered trust lands on the Shivwits Band and Kaibab Band reservations.
The restrictions banned:
• Open fires of any kind, except camp and charcoal fires within approved fire pits and grills provided for in developed recreation sites and picnic areas.
• Smoking, except within an enclosed vehicle, camp trailer, building, developed recreation site or while stopped in an area at least six feet in diameter that is barren or cleared to mineral soil.
• Fireworks, tracer ammunition or other incendiary devices in any location on federal, state and unincorporated private lands.
• The cutting, welding or grinding of metal in areas of dry vegetation on federal, state and unincorporated private lands in Washington County and outside of an enclosed building on the Arizona Strip.
Jessica Miller contributed to this story.