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.

As a precaution, the U.S. Forest Service closed the Soda Butte campground, where the camper was attacked, and the nearby Chief Joseph campground, both in the Gallatin National Forest. The sites are along U.S. 212, 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.