Fire crews battled Wednesday to contain a wildfire that has consumed nearly 160,000 hectares in the southwestern U.S. state of Arizona, and is showing no signs of letting up.

Officials say the blaze has forced more than 5,000 people to evacuate from mountain communities near Arizona's border with the state of New Mexico.

There have been no reports of injuries, but buildings have been destroyed.

The U.S. National Weather Service on Wednesday said the fire was “zero percent” contained. Some of the land burned is in parts of the Apache National Forest.

The blaze, which began more than a week ago, has sent smoke as far east as the state of Iowa and has forced planes to divert. Strong winds are helping carry the smoke.

The National Weather Service issued its “Red Flag” warning for critical fire weather conditions, saying the blaze has prompted an air quality alert.

Authorities have not determined the cause of the fire, now the second-largest in Arizona history.