HELENA, Mont. -- A bear attacked a person sleeping inside a tent early Thursday, leading authorities to close two campgrounds near Yellowstone National Park.

The camper suffered bite and claw marks on his arms while protecting himself. His name and age weren't disclosed. Authorities said he was taken to West Park Hospital in Cody, Wyo., which refused to release any information.

"Following the mauling, the campground was evacuated and it is now closed," Ken Britton, Gardiner District ranger, said in a prepared news release.

In addition to the Soda Butte campground, where the camper was attacked, the U.S. Forest Service also closed the nearby Chief Joseph campground, both in the Gallatin National Forest. The sites are along U.S. 212, near Cooke City, a few miles from the northeast entrance to Yellowstone National Park.

Forest spokeswoman Marna Daley said the bear was believed to be a grizzly. She didn't know how many people were evacuated from the campgrounds.

The camper apparently had stored his food properly, Daley said. She didn't know if he was camping alone.

The Forest Service said in a statement that the campgrounds will remain closed "until the bear is located or the immediate concern subsides."

The Montana Department of Fish, Wildlife and Parks will decide how to deal with the bear. In previous cases, problem bears have been relocated to more remote areas.

Colorado was also having bear problems this week. A mother bear and her cubs relocated after breaking into homes in the Beaver Creek area have returned.