NORDEN, Neb. (AP) — Firefighters are battling a blaze in north-central Nebraska that has burned at least 20,000 acres and damaged homes.

The fire was raging Saturday in parts of northern Brown County and southern and central Keya Paha County. Regional emergency manager Doug Fox says the fire’s leading edge was 6 to 7 miles wide as it moved through Keya Paha County.

Numerous homes and structures were damaged around the tiny community of Norden, although Fox says the exact number won’t be known until authorities survey the area.

A large air tanker from Rapid City, S.D. was dispatched to the area Saturday, as was a water-carrying helicopter from Lincoln.

No injuries were reported, but Fox says some firefighters were treated for symptoms of heat stress.