COLUMBUS, Ohio — State authorities are investigating a string of threats made against schools across Ohio.
Threats have caused evacuations or closures of some schools in the past week. The state Department of Education says it doesn't know how many, but says Ohio Homeland Security has reported "a number of bomb threats."
There have been no reports of explosives found or violence related to the threats.
Education spokeswoman Kim Norris says schools are urged to work closely with law enforcement, taking all threats seriously. They also ask students and parents to be alert and to report anything unusual.
In southwest Ohio, Butler County Sheriff Richard Jones reported Wednesday that two school districts in his county received unsubstantiated threats, with more in neighboring counties. Some schools described calls with voices sounding computer-generated or automated.