CLARKSVILLE, Tenn. (CLARKSVILLENOW) – Officials said students are safe and the school has been cleared after Clarksville High School (CHS) was placed on temporary lockdown Friday morning.

Principal Bryan Feldman said an unauthorized student was seen at the school.

“No threat was issued by the student, but in an effort to be cautious and protective of our student body and staff, we locked down the school and notified authorities,” Feldman said in an email.

The lockdown lasted approximately 20 minutes. Video surveillance showed the unauthorized person leaving the premises.

No further information has been released.