A kayaker discovered a man's body along the Potomac River in Great Falls National Park on Saturday, authorities say.

It appears 77-year-old Russell Larkin fell down a cliff on the Virginia side of the park and landed on rocks near the water, Montgomery County Fire and Rescue said. It's not clear what may have caused the fall.

Montgomery County and Fairfax County rescue workers went to an area near Rocky Island at the park about 9:45 a.m. and recovered the body.

The recovery effort was centered between Sandy Landing and Rocky Island, fire officials said.

The U.S. Park Police are leading the death investigation.