Two teens in Utah are facing criminal charges in separate cases after police said they made social media threats alluding to school shootings. Authorities concluded neither threat was serious.

A 17-year-old boy was arrested Thursday in Springville after he posted an online photo of himself or someone else holding an assault rifle. The caption read "Burrr it's cold."

Springville police Lt. Warren Foster said the teen faces several charges, including making a terroristic threat. He said police determined the boy had not plotted an attack and the gun shown in the photo was a replica.

"We firmly believe it was a bad decision on this young man's part to post such a ridiculous thing," Foster said.

A day earlier, police in Heber City arrested a 15-year-old boy after his friend posted a video on Snapchat showing him holding an assault rifle and warning high school classmates to not go to school the following day.

Heber City police Det. Tammy Thacker said the teen was arrested on suspicion of threat of violence and aggravated assault.

Thacker said a girl saw the video, showed it to her parents and they reported it to police.

She said police do not believe the boy had plans to act on the threat.