NORMAN, Okla. (AP) — Police in Norman have increased the number of officers at North High School after the Cleveland County Sheriff's Office received word of a possible threat to the school.

Capt. Tom Easley said in a news release Thursday that an anonymous phone caller to the sheriff's department Wednesday night reported hearing a threat made toward the school. Details of the threat were not released.

Easley says police and school officials are not convinced the threat is credible — but additional police officers were sent to the school as a precaution.