SALT LAKE COUNTY, Utah -- The Granite School District Police Department has issued military-grade AR-15 rifles to all of its officers.

The department bought the guns from the U.S. Military surplus system in an effort to better help officers keep children safe.

Since the 1999 Columbine High School shooting in Colorado, law enforcement officers said they have had to change the way they protect schools.

"Over the past 20 years law enforcement across the country has had to respond to the shootings in the malls, the shootings in schools, the shootings in theaters," said Granite School District Police Chief Randy Johnson. "And to be able to effectively protect the public, we need to be able to match the weapon that is being used by the person that's attempting to do harm. Most often a long gun is being used by these perpetrators."

Johnson said the weapons are just a small part of the plan to keep students safe. The department has also been installing a high-tech camera system in all of the district's schools so it can monitor what is going on from a dispatch center.