Jefferson County Public Schools officials say the district will operate under “heightened security” Friday after receiving a non-specific threat.

Superintendent Donna Hargens said the threat was made against unnamed schools, and didn’t specify whether the schools were public or private.

Under the heightened security, exterior school doors will be locked at all times, outside activities will be canceled and hallway traffic will be minimized and monitored on Friday, Hargens said.

She said the action is being taken out of an abundance of caution. Class schedules will not be changed.