PHOENIX - Firefighters are battling a forest fire burning out of control toward the Grand Canyon, fanned by strong winds and dry conditions, authorities said on Wednesday.

The so-called X Fire has burned 2,000 acres of the Kaibab National Forest in northern Arizona, and was burning toward the Grand Canyon National Park early on Wednesday, a spokeswoman for the forest service said.

"The fire is not contained at this time. It's still windy and moisture levels are low so we are concerned," said Margaret Hangan, a spokeswoman for the Kaibab National Forest.

Hangan said the fire was about a mile south of the Grand Canyon National Park boundary. There was no immediate threat to any buildings or visitor facilities, and the park remained open, she added.

The Grand Canyon is one of the biggest tourist draws in the United States, and attracts some five million visitors each year.