Updated: The Davenport Department is monitoring and investigating threats that have been posted on social media regarding a possible shooting at Davenport North High School.
Officers are following up on the information and have been in contact with administrators of the Davenport Community School District, police said.
"At this time the Davenport Community School District and the Davenport Police Department are aware of the social media threats that are causing concern. We have determined that the threats are not credible. There is no change to the daily schedule for any of our schools today," according to a statement released by the Davenport School District.
Similar posts have been made in the Des Moines area and Davenport police are working with law enforcement agencies there to determine if there are any connections to the local threats.
Johnston Community School District officials decided Monday night to cancel classes for Tuesday because of anonymous and threatening texts parents and others received around 8 p.m., Monday.
The suburban Des Moines district had a late start to school today so buildings could be checked.
Johnston Police Chief Dennis McDaniel said Tuesday that federal, state and local investigators couldn't substantiate "any credible or imminent threat."
Elsewhere, the Algona, Iowa, Community School District canceled its classes for today. The district said on its website that law enforcement told district administrators Tuesday night about a threat. The district said the credibility of the threat could not be determined before school starting time today, so classes were canceled.
Also, the Plattsmouth Community School District, an eastern Nebraska school district, canceled all classes today, citing a threat posted on social media.
Superintendent Richard Hasty says that, based on information from law enforcement, the threat about a shooting today at Plattsmouth Middle School appears credible. Hasty says officers have contacted one but not all of the suspects connected to the threats.
(The Associated Press contributed to this report)