(Radio Iowa) -(UPDATED 12:19-p.m.}  Several schools in Iowa are dealing with fake calls today (Tuesday) about possible shootings at district buildings. Classes were canceled at Clinton High School amid reports of possible gunshots having been fired at the school. The administration posted online that students were sheltering in place as police investigated — and in an update said police found no sign of any gunshots.

Muscatine police searched the Muscatine High School after a call and classes resumed when police turned up no threats. The Iowa City Police Department issued a statement saying it is communicating with the Iowa City Community School District regarding calls that are known as “Swatting.” The statement says the calls are not credible and there is no reason for concern at this time.

Officials with the Creston Community School District said that at approximately 10:30-a.m., the Union County Dispatch Center received a call from an unknown male reporting a shooting at the Creston High School. The caller claimed four students had been shot in a bathroom at the school. When officers arrived, they began an immediate sweep of the building and no evidence of a shooting was found. After clearing the building and consulting with district officials, the lock down was lifted. Officers were then sent to other buildings in the district while the lock down was lifted.

After consulting with the Iowa Department of Public Safety (DPS), it was determined that the incident was part of a state-wide “Swatting” call that was made to 30 police departments across Iowa. The Creston PD is working with the DPS to investigate the incident.