AR-15 rifles have been issued to school police in one Utah district.
The Granite School District Police Department said it has equipped all officers with the weapons in a bid to reassure parents.
Police Chief Randy Johnson said that the high-caliber rifles would help in "rapid response" situations.
"If we don't get in and stop the shooter, more people are going to die,” Johnson told NBC station KSL.
The department also installed a high-tech camera system in all the Granite District schools that lets them see what's going on from a dispatch center.
“Most shootings will be over very quickly and so if we arrive on the scene and we can hear gunshots, the officers are now being trained to go to the sound of the gunfire and stop the threat that is taking place,” Johnson said in a separate interview with The Salt Lake Tribune newspaper. “We know that we don’t have a lot of time to save people’s lives.”