By Courtney Sherwood

PORTLAND, Ore. (Reuters) - Two Oregon hikers who were assaulted by a beaver after they climbed onto its dam have been hospitalized for injuries incurred during the rare attack, law enforcement officials said on Friday.

Clayton Mitchell, 23, told the Deschutes County Sheriff's Office that he and a friend had been hiking along a river near his central Oregon home on Thursday when they climbed onto a beaver dam.

A resident beaver emerged from the dam, knocking Mitchell into the Deschutes River and trapping his friend, 31-year-old John Bailey, in a tangle of submerged logs, according to the sheriff's department incident report.

After Miller contacted the sheriff’s department for help, deputies called upon search and rescue volunteers to locate Bailey.

Searchers heard the trapped man call for help, but he freed himself and climbed out of the river just as deputies discovered his location, the report said of the incident, which is virtually unprecedented in central Oregon.

"I was just getting off shift when the report came in, and I didn't believe it," Deschutes County Sheriff's Department Lieutenant Joe Deluca said.

"I'm a city boy from the East Coast, and every day in Deschutes County I learn something new," Deluca added. "This time, I learned, don't mess with a beaver."

Mitchell and Bailey were both treated for non-life threatening injuries and are expected to recover. There was no information available on the status of the beaver, the sheriff's office said.

(Editing by Cynthia Johnston and Lisa Lambert)