NATCHITOCHES, La. (AP) -- Several buildings were evacuated at Northwestern State University and classes were canceled Monday after a high school housed on the campus received a bomb threat.

Officials said later Monday that no explosives were found and both the university and high school were declared safe.

Louisiana School for Math, Science and the Arts Principal Pat Widhalm says a student turned in a note found taped on a mirror that indicated explosives were in the school's main academic building. Shortly before noon, university police evacuated the school and campus buildings, including Fournet, Morrison, Kyser, Russell, Williamson and Bienvenu halls; the Family and Consumer Sciences Building, Watson Library; the A.A. Fredericks Center for Creative and Performing Arts, the NSU Alumni Center and the Friedman Student Union.

At least one campus entrance was closed.