Fire officials say 20 homes in the eastern Idaho city of Pocatello have burned and more are threatened in a fast-moving wildfire.

More than 1,000 people have been evacuated from some Pocatello neighborhoods and the community of Mink Creek. The Charlotte fire started Thursday afternoon, spreading quickly through bone-dry grass and brush.

Officials with the National Interagency Fire Center in Boise released a report Friday morning that said the fire was estimated at about 450 acres -- that's less than one square mile. It's showing extreme behavior, spreading quickly and sparking off small new blazes some distance from the main body of flames.

No injuries have been reported. Fire crews are assisted eight engines and one helicopter, and they hope to have the blaze contained sometime Saturday.