Fresno, CA -

A giant wildfire that's been raging out of control through the timbered slopes of the Sierra Nevada in California has spread into Yosemite National Park.

Authorities are urging more evacuations in nearby communities where thousands have already been forced out by the flames.

The week-long blaze has spread to more than 165 square miles and was only 2 percent contained.  The U.S. Forest Service says the fire is threatening about 4,500 homes. It already has destroyed four homes and 12 outbuildings. More than 2,000 firefighters are on the lines and one has been injured.

The fire has hit the park at the height of summer season. It has closed some back-country hiking but is not threatening the Yosemite Valley region, one of California's most popular tourist destinations. The glacier-carved valley offers visitors such iconic sights as the Half Dome and El Capitan rock formations and Bridalveil and Yosemite falls.