The canyon's North Rim, which is less popular with tourists than the South Rim, was being cleared due to a blaze called the White Sage Fire.

"Evacuees should travel calmly at a normal rate of speed and stay on paved roads only. North Rim day use is closed until further notice," the Park Service said in an order.

It was not immediately known how many people were being forced to leave the area.

The fire is burning outside the Grand Canyon National Park but approaching Jacob Lake, Arizona, a town known as the gateway to the North Rim.

One of the greatest wonders of the natural world, the Grand Canyon is the result of the Colorado River eating away at layers of red sandstone and other rock for millions of years, leaving a gash up to 18 miles (30 km) wide and more than a mile (1.6 km) deep.

Last year just under five million people visited the site.

Another popular site, Black Canyon of the Gunnison National Park in Colorado, was also closed Friday because of a wildfire.