Illegal campfire sparked Arizona wildfire: US officials

US authorities say an illegal campfire sparked the wildfire in Arizona that has prompted evacuations while burning 30 buildings and threatening about 1,000 homes and other structures.

Coconino National Forest officials said Tuesday that investigators determined that an abandoned campfire in an area where such fires are temporarily banned started the blaze, according to an AP report.

The fire, since it began Friday last, has burned nearly 18 square miles (46 square kilometres) in south of Flagstaff. An investigation is ongoing.