( CNN ) -- A days-long wildfire had covered more than 78,000 acres of Alaska 's Kenai National Wildlife Refuge by early Saturday , a state agency said . The Funny River Fire began burning Monday evening and was 20 % contained by early Saturday , Alaska 's Interagency Incident Management Team said . No evacuations or injuries have been reported . There were more than 409 firefighters battling the blaze . Officials say access to the fire is difficult . Investigators suspect human action was the cause , but this is still under investigation . The refuge is in Soldotna , south of Anchorage . Kenai Peninsula Borough Spokesman Brad Nelson said there are two subdivisions in the area of the fire . The combined population of these localities is approximately 5,000 residents . What to know about wildfires .
NEW : Wildfire scorches nearly 80,000 acres in Alaska . NEW : Blaze was 20 % contained by early Saturday . No evacuations or injuries have been reported .