Updated

An East Tennessee nuclear power plant has added security patrols after a weekend incident in which an officer exchanged gunfire with a man who then fled on a boat.

The FBI and the Nuclear Regulatory Commission are investigating the shooting early Sunday at Tennessee Valley Authority's Watts Bar nuclear power plant near Spring City, Tenn., about 60 miles southwest of Knoxville.

TVA spokesman Jim Hopson said a security officer spotted a man near the bank of the Tennessee River, which is on the property of the plant but outside the plant's fences.

The man, who was wearing a dark hooded sweatshirt, shot at the officer and struck the officer's vehicle. The officer was not injured and returned fire.