PRINCE.EDWARD.ISLAND (CBC) - Charlottetown Rural High School is operating under heightened security Wednesday after a shooting threat appeared on Facebook on Tuesday.

While police described Charlottetown Rural as locked down, classes are continuing.

All doors except the front door are locked and that door is guarded by uniformed police officers. Other officers are patrolling the grounds and the school building.

Police first heard about the threat in a complaint from a student at 9:30 p.m. Tuesday.

"There was a posting that come up on Facebook and all it said was, 'There will be a shooting tomorrow at chtn rural high school' and 'hide.' And that was the only person then the person disappeared," said Charlottetown police Sgt. Mike Quinn.

In following up the complaint, police found the posting appeared at 9 a.m. Tuesday.

The school was contacted and officials decided to keep the school open and proceed with heightened security.

"The threat, as far as we know at this time, appears to have been made by a fictitious character and it is not a threat against any specific person or persons," said Ricky Hood, transitions co-ordinator with the Eastern School District.

"With that level of information, and gathering what we could from the city police, it was agreed that we would try to have an operation at the school as normal as possible. We do believe the school is a safe environment for students and staff."

The principal briefed staff on the situation before classes started and then addressed students in their homerooms and provided all the information that was available.

"There was very little commotion at the time the information was passed on to the students. The bell rang and the vast majority of students moved on to their first class," said Hood.

Quinn said police will remain at the school as the investigations continues.