WAKE COUNTY, N.C. — The Wake County Sheriff's Office is investigating a late-night gunshot that ignited a security scare at Shearon Harris Nuclear Plant.

Progress Energy officials said that security officers at the plant discovered people trespassing about a quarter mile outside the plant Monday night, even though "no trespassing" signs were posted in the area.

Security at the nuclear plant has been under recent scrutiny, with federal investigators visiting last month to look into possible violations, including an incident last summer when a security guard heard shots while on patrol.

"We take matters of security very seriously," said Harris Vice President Neil Gannon. "Our highest priorities are the safety of the plant and the public. The dedicated force on-site at Harris works 24 hours a day, seven days a week to ensure that safety."

Wake County sheriff's deputies, who are investigating, believe the people were on the property hunting. The plant is near Harris Lake and Harris Lake County Park, which are operated by Progress Energy and the North Carolina Wildlife Resources Commission.