LOS ANGELES, July 11 (Xinhua) -- Parts of Grand Canyon National Park, a popular natural wonder in the U.S. west, were closed due to a fast-moving wildfire that reached about 8,700 acres (35.2 square kilometers) as of Friday afternoon, authorities said.

All visitors on the North Rim of Grand Canyon National Park, northwestern Arizona, were required to evacuate due to the advancing wildfire, dubbed the White Sage Fire, said park officials in a statement.

"All visitor access to the North Rim is closed until further notice," park officials said. They issued an extreme heat warning, as temperatures are expected to reach as high as 46 degrees Celsius.

The fire started Wednesday evening following a thunderstorm that moved through the area, according to InciWeb, an interagency all-risk incident web information management system provided by the United States Forest Service.

The fire made a significant run on Thursday, spotting and torching due to sustained winds, extremely dry conditions and low relative humidity, according to the agency's latest update.

Officials said the blaze remains zero contained so far. ■