A Utah junior high school was placed on lockdown today after a 15-year-old fired at least one round in a hallway -- but the teen was disarmed by his parents, who came to the school after being concerned that guns had gone missing from their house, police said.

Police dispatchers received a 911 call form a Mueller Park Junior High School teacher around 8:15 a.m. who stated that there was an individual in the school firing a weapon, according to Bountiful City Police Chief Tom Ross.

The teen's parents had gone to the school to look for their son and arrived before the shot was fired, Ross said. After they heard the gun go off, they were able to find and disarm him, Ross said. An officer arrived on scene within two minutes of the initial 911 call, and the teen was then taken into custody.

Students were in classrooms nearby when the weapon was discharged, but it is unclear if there was anyone else in the hallway at the time.

A shotgun and a handgun were recovered from the scene, but it is unclear which weapon was discharged. No charges have been filed as of yet.

The teen's parents went to the school because they were "worried" about their son and were "concerned that there were weapons missing from the home," Ross said. Police said that they also believed their son had been acting strangely.

A motive is not known at this time.

More than 100 law enforcement and emergency personnel responded, Ross said. The police department has done several drills over the years ever since the 1999 mass shooting at Columbine High School in Colorado.

The Davis School District announced that the lockdown had been lifted around 11 a.m., and school remained in session. Parents were not required to take their students home, but those who wished to were instructed to get their children from a nearby church. ABC News could not immediately reach the school district for comment.

Stephanie Neslen, whose son attends the school, said the drive to pick him up was the longest in her life.

"He texted me and said, 'Mom, it's not a drill. I heard a gun,'" Neslen told ABC Salt Lake City affiliate KTVX.